Answer:
The pineal, hypothalamus, and pituitary are located in the BRAIN
The thyroid, parathyroid, and thymus are located in the THROAT
The adrenals, pancreas, testes, and ovaries are located in the NEAR THE KIDNEY
Explanation:
The pineal, hypothalamus, and pituitary are located in the BRAIN
The thyroid, parathyroid, and thymus are located in the THROAT
The adrenals, pancreas, testes, and ovaries are located in the NEAR THE KIDNEY
Answer:
Throat
Abdomen
Brain
Explanation:
These are correct!
1. The chemical formula for sodium bromide is NaB.*
True
False
Answer:
NaBr
Explanation:
Bromine's symbol is Br, not B, for B is for Boron
How much of a 0.250 M lithium hydroxide is required to neutralize 20.0 mL of 0.345M chlorous acid?
Answer:
27.6mL of LiOH 0.250M
Explanation:
The reaction of lithium hydroxide (LiOH) with chlorous acid (HClO₂) is:
LiOH + HClO₂ → LiClO₂ + H₂O
That means, 1 mole of hydroxide reacts per mole of acid
Moles of 20.0 mL = 0.0200L of 0.345M chlorous acid are:
0.0200L ₓ (0.345mol / L) = 6.90x10⁻³ moles of HClO₂
To neutralize this acid, you need to add the same number of moles of LiOH, that is 6.90x10⁻³ moles. As the LiOH contains 0.250 moles / L:
6.90x10⁻³ moles ₓ (1L / 0.250mol) = 0.0276L of LiOH =
27.6mL of LiOH 0.250MOlive oil has a density of 0.92g/ml. How much would 1.0 Liter of olive oil weigh in grams?
Answer:
9.2x10²g
Explanation:
Data obtained from the question include the following:
Density = 0.92g/ml
Volume = 1L = 1 x 1000 = 1000mL
Mass =..?
Density is simply defined as the mass of the substance per unit volume of the substance. Mathematically it can be represented as:
Density = Mass /volume.
Mass = Density x volume
Mass = 0.92 x 1000
Mass = 9.2x10²g.
Therefore, 1L of olive will weigh 9.2x10²g.
The reaction described by H2(g)+I2(g)⟶2HI(g) has an experimentally determined rate law of rate=k[H2][I2] Some proposed mechanisms for this reaction are: Mechanism A (1) H2(g)+I2(g)−→k12HI(g)(one-step reaction) Mechanism B (1) I2(g)⥫⥬=k−1k12I(g)(fast, equilibrium) (2) H2(g)+2I(g)−→k22HI(g) (slow) Mechanism C (1) I2(g)⥫⥬=k−1k12I(g)(fast, equilibrium) (2) I(g)+H2(g)−→k2HI(g)+H(g) (slow) (3) H(g)+I(g)−→k3HI(g) (fast) Which of these mechanisms are consistent with the observed rate law? mechanism A mechanism C mechanism B In 1967, J. H. Sullivan showed that this reaction was dramatically catalyzed by light when the energy of the light was sufficient to break the I−I bond in an I2 molecule. Which mechanism or mechanisms are consistent with both the rate law and this additional observation? mechanism A mechanism C mechanism B
Answer:
Mechanism A and B are consistent with observed rate law
Mechanism A is consistent with the observation of J. H. Sullivan
Explanation:
In a mechanism of a reaction, the rate is determinated by the slow step of the mechanism.
In the proposed mechanisms:
Mechanism A
(1) H2(g)+I2(g)→2HI(g)(one-step reaction)
Mechanism B
(1) I2(g)⇄2I(g)(fast, equilibrium)
(2) H2(g)+2I(g)→2HI(g) (slow)
Mechanism C
(1) I2(g) ⇄ 2I(g)(fast, equilibrium)
(2) I(g)+H2(g) ⇄ HI(g)+H(g) (slow)
(3) H(g)+I(g)→HI(g) (fast)
The rate laws are:
A: rate = k₁ [H2] [I2]
B: rate = k₂ [H2] [I]²
As:
K-1 [I]² = K1 [I2]:
rate = k' [H2] [I2]
Where K' = K1 * K2
C: rate = k₁ [H2] [I]
As:
K-1 [I]² = K1 [I2]:
rate = k' [H2] [I2]^1/2
Thus, just mechanism A and B are consistent with observed rate law
In the equilibrium of B, you can see the I-I bond is broken in a fast equilibrium (That means the rupture of the bond is not a determinating step in the reaction), but in mechanism A, the fast rupture of I-I bond could increase in a big way the rate of the reaction. Thus, just mechanism A is consistent with the observation of J. H. Sullivan
Assign priorities in the following set of substituents according to Cahn-Ingold-Prelog rules.-Cl, -OH, -CH_2OH, -CH_2SHA B C D(Provide your ranking through a string like abed, starting with the one with the highest priority. Your answer does not need to be capitalized.)
Answer:
1) [tex]-Cl[/tex]
2) [tex]-OH[/tex]
3) [tex]-CH_2SH[/tex]
4) [tex]-CH_2OH[/tex]
Explanation:
We have the substituents:
a) [tex]-Cl[/tex]
b) [tex]-OH[/tex]
c) [tex]-CH_2OH[/tex]
d) [tex]-CH_2SH[/tex]
If we remember that Cahn-Ingold-Prelog rules the highest priority is given by the atomic number. Therefore the highest priority is "Cl" (an atomic number equal to 17), the next one is "OH" due to the oxygen (an atomic number equal to 8). For c) and d) we have a carbon bonded to the chiral carbon, therefore we have to check the next atom. The difference between c) and d) are the "O" and "S" atoms, the atom with the highest atomic number is "S" (an atomic number equal to 16) therefore the highest priority is for d) and then c). So finally, the priority is:
1) [tex]-Cl[/tex]
2) [tex]-OH[/tex]
3) [tex]-CH_2SH[/tex]
4) [tex]-CH_2OH[/tex]
I hope it hepls!
Which hormones are secreted from the posterior pituitary gland?
a. Growth hormone
b. Oxytocin
C. ACTH
d. PTH
the answer is b
The posterior pituitary secretes two important endocrine hormones—oxytocin and antidiuretic hormone
The potential in an electrochemical cell, E, is related to the Gibb's free energy change (ΔG) for the overall cell redox reaction: (1) ΔG0 = - n F E0 where n is the number of electrons transferred during the redox reaction, F is Faraday's constant (96,500 C / mol), and the superscript 0 indicates standard conditions (1 atm, 1 M concentrations, and 25 °C). Thus, a measurement of the cell voltage at standard conditions can be used to determine ΔG0. As an example, the following cell reaction: Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(m) generates a cell voltage of +1.10 V under standard conditions. Calculate and enter delta G degree (with 3 sig figs) for this reaction in kJ/mol.
Answer:
Explanation:
As an example, the following cell reaction: Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(m) generates a cell voltage of +1.10 V under standard conditions. Calculate and enter delta G degree (with 3 sig figs) for this reaction in kJ/mol.
Zn(s) + Cu2+(aq) → Zn2+(aq) + Cu(m)
ΔG = ΔG° + RTInQ
Q = 1
ΔG = ΔG°
ΔG = =nFE°
n=no of electrons transfered.
E° = 1.1v
ΔG° = -2 * 96500 * 1.10
= -212300J
ΔG° =-212.3kJ/mol
Therefore, the ΔG° = -212.3kJ/mol0.76 g of lead(2) nitrate was dissolvedin 50.00ml of water a d treated with 25.00 ml of 0.2010M sodium sulfate inoder to determine a content of lead 2 ion. A white precipitate was formed and it was collected and dried. Calculate the amount of precipitate formed in this reaction
Answer:
Mass of precipitate (PbSO₄) formed = 0.696 g
Explanation:
The reaction of Lead II Nitrate and Sodium Sulfate is given as
Pb(NO₃)₂ (aq) + Na₂SO₄ (aq) → 2NaNO₃ (aq) + PbSO₄ (s)
The precipitate from this reaction is the PbSO₄
0.76 g of Pb(NO₃)₂ is available for reaction, we convert to number of moles
Number of moles = (Mass)/(Molar Mass)
Mass = 0.76 g
Molar mass of Pb(NO₃)₂ = 331.2 g/mol
Number of moles of Pb(NO₃)₂ = (0.76/331.2) = 0.002294686 moles = 0.002295 moles
25.00 ml of 0.2010M sodium sulfate is available for the reaction, we also conert to number of moles.
Number of moles = (Concentration in mol/L) × (Volume in L)
Concentration of Na₂SO₄ in mol/L = 0.201 M
Volume of Na₂SO₄ in L = (25/1000) = 0.025 L
Number of moles of Na₂SO₄ = 0.201 × 0.025 = 0.005025 moles
From the stoichiometric balance of the reaction, 1 mole of Pb(NO₃)₂ reacts with 1 mole of Na₂SO₄
Hence, this indicates that Pb(NO₃)₂ is the limiting reagent as it is in short supply and it will therefore dictate the amount of precipitate (PbSO₄) formed.
1 mole of Pb(NO₃)₂ gives 1 mole of the precipitate (PbSO₄)
0.002295 mole of Pb(NO₃)₂ will give 0.002295 mole of the precipitate (PbSO₄)
Mass = (Number of moles) × (Molar mass)
Number of moles of precipitate (PbSO₄) formed = 0.002295 mole
Molar mass of PbSO₄ = 303.26 g/mol
Mass of precipitate (PbSO₄) formed = 0.002295 × 303.26 = 0.6958864734 = 0.696 g
Hope this Helps!!!
he Punnett square shows the possible genotype combinations for the offspring of two parents. What are the genotypes of the parents? Gg and Gg GG and GG gg and gg Gg and gg
Answer:
Its A! Gg and Gg
Explanation:
Where does the stored energy in these cabbage leaves come from ?
Answer:
The energy in cabbage leaves comes from the light from the sun.
Explanation:
The plant keeps the light (in the leaves) as energy to help make it grow.
The pressure exerted by 1.5 mol of gas in a 13 L flask at 22 °C is ____ kPa
Answer:
282.7KPa
Explanation:
Step 1:
Data obtained from the question.
Number of mole of (n) = 1.5 mole
Volume (V) = 13L
Temperature (T) = 22°C = 22 + 273°C = 295K
Pressure (P) =..?
Gas constant (R) = 0.082atm.L/Kmol
Step 2:
Determination of the pressure exerted by the gas.
This can be obtained by using the ideal gas equation as follow:
PV = nRT
P = nRT /V
P = 1.5 x 0.082 x 295 / 13
P = 2.79atm.
Step 3:
Conversion of 2.79atm to KPa.
This is illustrated below:
1 atm = 101.325KPa
Therefore, 2.79atm = 2.79 x 101.325 = 282.7KPa
Therefore, the pressure exerted by the gas in KPa is 282.7KPa
Pressure is defined as the force exerted by the molecules colliding with the surface of the object and other surfaces. The ideal gas follows the general gas law equation, PV = nRT.
The pressure exerted by the gas is 282.7 KPa.
Given:
Pressure (P) = ?
Gas constant (R) = 0.082atm.L/Kmol
Temperature (T) = 22°C = 22 + 273°C = 295K
Volume (V) = 13L
Number of mole of (n) = 1.5 mole
Now, using the ideal gas equation:
PV = nRT
Substituting the values, we get:
P x 13 = 1.5 x 0.082 x 295
P x 13 = 36.285
P = [tex]\dfrac{36.285}{13}[/tex]
Pressure = 2.79 atm.
Also, 1 atm = 101.32 KPa
2.79 atm = 2.79 x 101.32 = 282.7 KPa.
Thus, the pressure exerted by the gas molecules is 282.7 KPa.
To know more about ideal gas law, refer to the following link:
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A galvanic (voltaic) cell consists of an electrode composed of magnesium in a 1.0 M magnesium ion solution and another electrode composed of silver in a 1.0 M silver ion solution, connected by a salt bridge. Calculate the standard potential for this cell at 25 °C.
Answer:
3.17 V
Explanation:
The cell is operating under standard conditions. These standard conditions include; that the reaction takes place at 298 Kelvin (room temperature), the pressure of the system is 1 atmosphere (standard pressure), and the solutions have a Molarity of 1.0 M for both the anode and cathode solutions. All these conditions are satisfied in the cell under review in the question.
Hence;
E°anode (magnesium)= -2.37 V
E°cathode (silver) = 0.80 V
E°cell= E°cathode -E°anode
E°cell= 0.80-(-2.37)
E°cell= 0.80 + 2.37
E°cell= 3.17 V
Hence the standard cell potential of this cell at 25°C is 3.17 V
Answer:
The standard potential at 25ºC is 3.17 V.
Explanation:
The anode in a galvanic cell is the electrode at which oxidation occurs and the cathode is the electrode at which reduction occurs.
The overall cell reaction will be the sum of two half-cell reactions. The standard reduction potentials are:
Mg²⁺ (1.0 M) + 2e⁻ → Mg (s) Eº = -2.37
Ag⁺ (1.0 M) + e⁻ → Ag (s) Eº= +0.80
Since the reactants are in their standard states (1.0 M) and at 25ºC we can write the half-cell reactions as follows:
Anode (oxidation): Mg (s) → Mg²⁺ (1.0 M) + 2e⁻
Cathode (reduction): 2Ag⁺ (1.0 M) + 2e⁻ → 2Ag (s)
Overall: Mg (s) +2 Ag⁺ (1.0 M) + 2e⁻ → 2Ag (s) + Mg²⁺ (1.0 M) + 2e⁻
In order to balance the overall equation we multiply the reduction of Ag⁺ by 2. We can do so because, as an intensive property, E° is not affected by this procedure.
The standard emf of the cell, E°cell , which is composed of a contribution from the anode and a contribution from the cathode, is given by:
[tex] Eº cell = Eº cathode - Eº anode [/tex]
[tex] Eº cell = EºAg⁺/Ag - Eº Mg²⁺/Mg [/tex]
[tex] Eº cell =0.80 V - (-2.37 V) [/tex]
Eº cell = 3.17 V
Which evidence supports the idea that Cosmic Microwave Background radiation is a remnant of the Big Bang?
A. Its temperature is uniform.
B. Its temperature fluctuates greatly.
C. Its mass fluctuates greatly.
D. Its mass is uniform.
Answer:
A. Its temperature is uniform.
Explanation:
Cosmic Microwave Background radiation is a remnant of the Big Bang talks about the universe being very hot thereby causing its expansion with a corresponding cooling of the gases within it. The Cosmic Microwave Background radiation being what is left of the radiation after the Big Bang occurrence.
The temperature was uniform with very little fluctuations which makes the A the right choice.
Answer:
a
Explanation:
If the specific heat of gold is 0.13 J/gC, what is the amount of energy (heat) required to raise 30.0g of gold from 15 degrees Celsius to 41 degrees Celsius?
Answer: The amount of energy required is 101 Joules
Explanation:
The quantity of heat required to raise the temperature of a substance by one degree Celsius is called the specific heat capacity.
[tex]Q=m\times c\times \Delta T[/tex]
Q = Heat absorbed = ?
m= mass of gold = 30.0 g
c = specific heat capacity of gold = [tex]0.13J/g^0C[/tex]
Initial temperature of the water = [tex]T_i[/tex] = 15°C
Final temperature of the water = [tex]T_f[/tex] = 41°C
Change in temperature ,[tex]\Delta T=T_f-T_i=(41-15)^0C=26^0C[/tex]
Putting in the values, we get:
[tex]Q=30.0g\times 0.13J/g^0C\times 26^0C[/tex]
[tex]Q=101J[/tex]
The amount of energy required is 101 Joules
Acetone is a solvent used in fingernail polish remover. Acetone is polar. It will form
solutions, or be soluble, in all the following except
O A. ethanol, which has molecules that have
one end with a slight charge
B. ammonia, which is made of molecules with
a slightly negative nitrogen atom and three
slightly positive hydrogen atoms
O C. water, which has oxygen atoms with a
slight negative charge
D. vegetable oil, which has atoms that share
electrons equally, so that there is no charge
difference
Read Question
Correct:
Answer:
d
Explanation:
After doing a correct and careful recrystallization, you isolate your product by filtration. Which of the following will be present in the mother liquor? (select all that apply)
a. Impurities
b. Large amount of product
c. Recrystallizing solvent
d. Small amount of produc
Answer:
a. Impurities
c. Recrystallizing solvent
Explanation:
In this type of reaction the products are never considered totally pure, that is why as a final product it must always be taken into account that it is proportional, it will be a recrystallization solvent and other impurities with which the products were mixed.
Each of these geometric shapes has a different number of sides. Arrange the shapes in order from the shape with the greatest number of sides to the shape with the fewest number of sides. Rank these shapes from greatest to fewest number of sides. To rank items as equivalent, overlap them.
triangle , square, rectangle, octagon, hexagon, pentagon
1. Octagon (8 sides)
2. Hexagon (6 sides)
3. Pentagon (5 sides)
4. Square/Rectangle (4 sides)
5. Triangle (3 sides)
Hope this helps :)
Determine the mass of CaBr2 needed to create a 500. ml solution with a concentration of 1.15 M.
Answer:
[tex]m_{CaBr_2}=115gCaBr_2[/tex]
Explanation:
Hello,
In this case, we remember molarity is defined as the ratio of the moles of the solute to the volume of the solution in litres, therefore, for the given concentration and volume, we should solve the moles of calcium bromide to subsequently compute the mass, as shown below:
[tex]M=\frac{n}{V}\\ \\n=M*V=1.15\frac{mol}{L} *500mL*\frac{1L}{1000mL}=0.575mol[/tex]
Next, since molar mass of calcium bromide is 200 g/mol, we can compute the mass:
[tex]m_{CaBr_2}=0.575mol*\frac{1mol}{200g} \\\\m_{CaBr_2}=115gCaBr_2[/tex]
Regards.
Structurwl formula for (CH3)2CHCH2OH
Answer:
Isobutanol (IUPAC nomenclature: 2-methylpropan-1-ol)
Explanation:
Isobutanol (IUPAC nomenclature: 2-methylpropan-1-ol) is an organic compound with the formula (CH3)2CHCH2OH (sometimes represented as i-BuOH). Hope this helped!
Br2(g) + 3 F2(g) ⇄ 2 BrF3(g) Kp = 5.4 × 108 0.30 atm of Br2 and 0.60 atm of F2 are placed in a 3.0 L container and the system is allowed to reach equilibrium. Calculate the pressureof Br2 at equilibrium.
Answer:
The pressure at equilibrium of Br₂ is 0.10048 atm
Explanation:
Based on the reaction:
Br₂(g) + 3 F₂(g) ⇄ 2 BrF₃(g)
Kp is defined as:
[tex]Kp = \frac{P_{BrF_3}^2}{P_{Br_2}P_{F_2}^3}[/tex] = 5.4x10⁸
If initial pressures of Br₂ and F₂ are 0.30atm and 0.60atm respectively, the pressures in equilibrium are:
Br₂ = 0.30atm - X
F₂ = 0.60atm - 3X
BrF₃ = 2X
Replacing in Kp formula:
5.4x10⁸ = [2X]² / [0.30atm - X] [0.60atm - 3X]³
5.4x10⁸ = 4X² / [0.30 - X] [0.216 - 3.24 X + 16.2 X² - 27 X³]
5.4x10⁸ = 4X² / 0.0648 - 1.188 X + 8.1 X² - 24.3 X³ + 27 X⁴
Solving for X:
X = 0.3000 → False answer because produce negative concentrations.
X = 0.19952. Replacing in equation of Br₂:
Br₂ = 0.30atm - 0.19952atm = 0.10048 atm
Convert 3.4 x 10^23 molecules of NaCl to grams
Answer:
[tex]m_{NaCl}=33g[/tex]
Explanation:
Hello,
In this case, in order to compute the grams of sodium chloride starting by the molecules, the first step is to compute the moles contained in the given amount of molecules by using the Avogadro's number:
[tex]n_{NaCl}=3.4x10^{23}molecules*\frac{1mol}{6.022x10^{23}molecules} =0.56mol[/tex]
Then, by using the molar mass of sodium chloride (58.45 g/mol) we can directly compute the grams:
[tex]m_{NaCl}=0.56mol*\frac{58.45g}{1mol} \\\\m_{NaCl}=33g[/tex]
Regards.
A boy reached his home by riding motorcycle within 5 minutes by travelling 8 km distance ,them what is his average velocity?
Answer:
1.6
Explanation:
velocity=distance/time
=8/5
Based on the activity series provided which reactants will form products? F>Cl>Br>l
Answer:
CuI₂ + Br₂
Explanation:
Answer:
a
Explanation:
What is the kinetic energy,in J,of an Ar atom moving at a speed of 650 m/s
Answer:
1.40 × 10⁻²⁰ J
Explanation:
Step 1: Calculate the mass of 1 atom of argon
The molar mass of argon is 39.95 g/mol, that is, 6.02 × 10²³ atoms of Ar have a mass of 39.95 g. We can use this relation to find the mass of 1 atom of Ar.
[tex]\frac{39.95g}{1mol} \times \frac{1mol}{6.02 \times 10^{23}atom } =6.64 \times 10^{-23}g/atom[/tex]
Step 2: Convert the mass of 1 atom of argon to kilograms
We will use the relationship 1 kg = 1,000 g.
[tex]6.64 \times 10^{-23}g \times \frac{1kg}{1,000g} =6.64 \times 10^{-26}kg[/tex]
Step 3: Calculate the kinetic energy of 1 atom of Ar moving at 650 m/s
[tex]E=\frac{1}{2} \times m \times v^{2} = \frac{1}{2} \times 6.64 \times 10^{-26}kg \times (650m/s)^{2} = 1.40 \times 10^{-20}J[/tex]
The kinetic energy of an Ar atom at a speed of 650 m/s is 1.40 × 10⁻²⁰ J
Kinetic Energy:
Kinetic energy is directly proportional to the mass of the object and to the square of its velocity:
K.E = [tex]\frac{1}{2}[/tex] x [tex]m[/tex] x [tex]v^{2}[/tex]
Step 1: Calculate the mass of 1 atom of argon
The molar mass of argon is 39.95 g/mol, that is, 6.02 × [tex]10^{-23}[/tex] atoms of Ar have a mass of 39.95 g. We can use this relation to find the mass of 1 atom of Ar.
[tex]\frac{39.95 g}{1 mol} * \frac{1 mol}{1,000 g} = 6.64 * 10^{-26} g/ atom[/tex]
Step 2: Convert the mass of 1 atom of argon to kilograms
We will use the relationship 1 kg = 1,000 g.
6.64 x [tex]10^{-23}[/tex] g x [tex]\frac{1 kg}{1,000g}[/tex] = 6.64 x [tex]10^{-26}[/tex] kg
Step 3: Calculate the kinetic energy of 1 atom of Ar moving at 650 m/s
E= [tex]\frac{1}{2}[/tex] x [tex]m[/tex] x [tex]v^{2}[/tex] = [tex]\frac{1}{2}[/tex] x 6.64 x [tex]10^{-26}[/tex] kg x (650 m/s)² = 1.40 x [tex]10^{-20}[/tex] J
Learn more:
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The pressure in car tires is often measured in pounds per square inch (lb/in.2), with the recommended pressure being in the range of 25 to 45 lb/in.2. Suppose a tire has a pressure of 34.5 lb/in.2 . Convert 34.5 lb/in.2 to its equivalent in atmosphere
Answer:
2.35 atm
Explanation:
1 atm = 14.70 lb/in²
[tex]p = \text{34.5 lb/in}^{2} \times \dfrac{\text{1 atm}}{\text{14.70 lb/in}^{2}} = \textbf{2.35 atm}[/tex]
Just as carbon dating is used to measure the age of organic material, Argon-40 can be used to measure the age of rocks. A volcanic eruption melts a large chunk of rock, and all gasses are expelled. After cooling, Argon-40 accumulates from the ongoing decay of potassium-40 in the rock (t_1/2 = 1.25E9 years). When a piece of rock is analyzed, it is found to contain 1.38 mmol of potassium-40 and 1.14 mmol of Argon-40. How long did the rock cool?
Answer:
3.77 mg of K-40 decayed into Ar-40.
Data:
1) K-40, Ca-40, Ar-40: all three have the same atomic mass
2) 90% of the potassium-40 will decay into calcium-40
3) 10% of the potassium-40 will decay into argon-40.
4) K-40 inside the rock = 0.81 mg
5) Ar-40 trapped = 0.377 mg
Soltuion:
1) 0.377 mg of Ar-40 is the 10% of the mass of the K-40 that decayed
=> x * 10% = 0.377 mg => x * 0.1 = 0.377mg
=> x = 0.377 mg / 0.1 = 3.77 mg
That means that 3.77 mg of K-40 decayed into Ar-40. And this is the answer to the question.
Additionaly, you can analyze the content of all K-40 and Ca-40, to understand better the case.
2) The mass of the K-40 that decayed into Ca-40 is 9 times (ratio 9:1) the amount that decayed into Ar-40 =>
mass of K-40 that decayed into Ca-40 = 9 * 0.377 = 3.393 mg
3) Total amount of K-40 that decayed = amount that decayed into Ar-40 + amount that decayed into Ca-40 = 0.377mg + 3.393mg = 3.77 mg
4) Original amount of K-40 = amount of K-40 that decayed + amount of K-40 present in the rock = 3.77mg + 0.81 mg = 4.58 mg
5) amount of K-40 that decayed into Ar-40 as percent
% = [3.77 mg / 4.58mg] * 100 = 82.31 %.
1. Legătura covalentă este legătura chimică ce se stabileşte: a) prin punere în comun de electroni; b) prin transfer de electroni; c) prin punere în comun sau prin transfer de electroni. 2. Legătura covalentă se stabileşte între: a) două metale ; b) două nemetale; c) un metal şi un nemetal. 3. O legătură covalentă se stabileşte: a) între hidrogen şi sodiu ; b) între azot şi hidrogen; c) între aluminiu şi oxigen.. 4. Legăturile covalente sunt de două feluri: a) legături covalente simple si legaturi covalente duble; b) legături covalente polare şi legături covalente nepolare; c) nici un raspuns nu este corect. 5. Selectează substanțele în moleculele cărora atomii sunt uniți prin legătură ionică: a) oxid de fosfor P2O5; b)clorură de potasiu KCl; c) apă H2O
Answer:
1) Option A is correct.
The covalent bond is the chemical bond that is established by pooling of electrons.
2) Option B is correct.
The covalent bond is established between two non-metals.
3) Option B is correct.
A covalent bond is established between nitrogen and hydrogen.
4) Option B is correct.
Covalent bonds are of two types; polar covalent bonds and non-polar covalent bonds.
5) Option B is correct.
Select the substances in the molecules of which the atoms are united by ionic bond.
potassium chloride KCl
1) Opțiunea A este corectă.
Legătura covalentă este legătura chimică care se stabilește prin punerea în comun a electronilor.
2) Opțiunea B este corectă.
Legătura covalentă este stabilită între două nemetale.
3) Opțiunea B este corectă.
Se stabilește o legătură covalentă între azot și hidrogen.
4) Opțiunea B este corectă.
Legăturile covalente sunt de două tipuri; legături covalente polare și legături covalente nepolare.
5) Opțiunea B este corectă.
Selectați substanțele din moleculele cărora atomii sunt uniți prin legătură ionică. clorură de potasiu KCl
Explanation:
English Translation
1) The covalent bond is the chemical bond that is established: a) by pooling electrons; b) by electron transfer; c) by pooling or electron transfer.
2) The covalent bond is established between: a) two metals; b) two non-metals; c) a metal and a non-metal.
3) A covalent bond is established: a) between hydrogen and sodium; b) between nitrogen and hydrogen; c) between aluminum and oxygen.
4) Covalent bonds are of two types: a) single covalent bonds and double covalent bonds; b) polar covalent bonds and non-polar covalent bonds; c) no answer is correct.
5) Select the substances in the molecules of which the atoms are united by ionic bond: a) phosphorus oxide P2O5; b) potassium chloride KCl; c) H2O water
Solution
Covalent bonds are bonds that result from the sharing/pooling of electrons by two non-metallic atoms. When the electronegativity difference between the two atoms in a cobalent bond is substantial, a polar covalent bond results (in which the shared electrons are closer to the more electronegative atom of the pair). If the electronegativity difference isn't significant, a non-polar covalent bond ensues, in which the shared electrons are approximately equidistant from both atoms.
1) The covalent bond is the chemical bond that is established by pooling of electrons.
Already explained above.
2) The covalent bond is established between two non-metals.
Already explained too.
3) A covalent bond is established between nitrogen and hydrogen.
Of the three options, only option B contains two elements, nitrogen and hydrogen, which are both non-metals amd this satisfy the condition for the formation of a covalent bond.
4) Covalent bonds are of two types; polar covalent bonds and non-polar covalent bonds.
Already explained above.
5) Select the substances in the molecules of which the atoms are united by ionic bond.
potassium chloride KCl
Ionic bonds result from the transfer of electrons from metals (electropositive elements) to non-metals (electronegative elements). Of the 3 options provided, only potassium chloride is a coming together of a metal and a non metal.
In Romanian/In limba romana
Legăturile covalente sunt legături care rezultă din împărțirea / îmbinarea electronilor de către doi atomi nemetalici. Când diferența de electronegativitate între cei doi atomi dintr-o legătură cobalentă este substanțială, rezultă o legătură covalentă polară (în care electronii partajați sunt mai apropiați de atomul mai electronegativ al perechii). Dacă diferența de electronegativitate nu este semnificativă, apare o legătură covalentă non-polară, în care electronii partajați sunt aproximativ echidistanți de la ambii atomi.
Legăturile ionice rezultă din transferul electronilor de la metale (elemente electropozitive) la nemetalele (elemente electronegative).
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Aqueous solutions of ammonium oxalate and lithium acetate react.
Answer:
The reaction is a double displacement reaction
Explanation:
Let us consider the reaction equation of the reaction between ammonium oxalate and lithium acetate.
(NH4)2C2O4(aq) +2 CH3COOLi(aq) -------> 2NH4CH3CO2(aq) + Li2C2O4(s)
This is a displacement reaction. A double displacement reaction is a type of reaction in which two reactants exchange their ions to form two new compounds. Double displacement reactions usually lead to the formation of a solid product which is also called a precipitate.
The general form of a Double displacement reaction is of the format:
AB + CD → AD + CB
Where A,B,C and D represents different ions respectively.
A double displacement reaction can also be referred to as salt metathesis reaction, double replacement reaction, exchange reaction, or a double decomposition reaction, although the latter term is more strictly used when one or more of the reactants does not dissolve in the solvent.
In the laboratory hydrogen gas is usually made by the following reaction:Zn(s)+2HCl(aq)=H2(g)+ZnCl2(aq)How many liters of H2 gas , collected over water at an atmospheric pressure of 752 mmHg and a temperture of 21 Co, can made from 3.566 g of Zn and excess HCl?the partial pressure of water vapor is 18.65mmHg at 21C0.A) 0.68LB) 2.72LC) 1.36LD) 1.33LE) 0.0975L
Answer:
The correct answer is option C, that is, 1.36 L.
Explanation:
The reaction mentioned in the question is:
Zn (s) + 2HCl (aq) ⇒ H2 (g) + ZnCl2 (aq)
It is clear that one mole of zinc is generating one mole of hydrogen gas as seen in the reaction. The mass of zinc mentioned in the question is 3.566 grams, the no of moles can be determined by using the formula,
n = mass / molecular mass
The molecular mass of zinc is 65.39 g/mol, now putting the values in the formula we get,
n = 3.566 g/ 65.39 g/mol
= 0.0545 mol
Based on the question, the partial pressure of water vapor is 18.65 mmHg and the atmospheric pressure is 752 mmHg. Therefore, the pressure of hydrogen gas will be,
Pressure of hydrogen gas (H2) = 752 mmHg - 18.65 mmHg
= 733.35 mmHg
The liters of hydrogen gas produced can be calculated by using the equation, PV =nRT
R is the gas constant, having the value 62.36 L mmHg/K/mol and T is the temperature (273 + 21 = 294 K).
Now putting the values in the equation we get,
733.35 mmHg * V = 0.0545 mol * 62.36 mmHg/K/mol * 294 K
= 999.19 L / 733.35
= 1.36 L
Hence, the volume of hydrogen gas is 1.36 L.
convert 4.56 cm to mm
Answer:
45.6 mm
Explanation:
1 centimeter = 10 millimeter
4.56 cm = x mm
x = 4.56 × 10
= 45.6 mm