The current, most modern view of the atom is the ___
model.
A. Rutherford
B. quantum mechanical
C. Bohr
D. Thomson
E. Einstein
A truck with a mass of 30,000 kg is traveling down a Michigan Highway at a speed of 32 m/s when it sees a roadblock and must come to a sudden stop in 13 seconds. Given a uniform acceleration, find the following:
What property of matter causes convection currents?
density
mass
volume
weight
Answer:
if i am correct it is density =)
Explanation:
Answer:
density
Explanation:
&*
if the rate of appearance of no2 is equal to 8.00mol/min at a particular moment, what is the rate of dissapearce of N2O5 at that moment
Answer:
[tex]r_{N_2O_5}=-4.00mol/min\[/tex]
Explanation:
Hello.
In this case, since the chemical reaction is:
[tex]2N_2O_5\rightarrow 4NO_2+O_2[/tex]
We can write the rate ratio between N2O5 and NO2 as shown below:
[tex]\frac{1}{-2} r_{N_2O_5}= \frac{1}{4} r_{NO_2}[/tex]
Since N2O5 is consumed and NO2 produced at a rate of 8.00 mol/s, therefore, the rate of disappearance is N2O5 is:
[tex]r_{N_2O_5}= \frac{-2}{4} r_{NO_2}\\\\ r_{N_2O_5}=\frac{-1}{2} *8.00 mol/min\\\\ r_{N_2O_5}=-4.00mol/min[/tex]
Which is negative since N2O5 is a reactant.
Best regards!
Which of the following is a chemical property?
A. Gallium metal melts in your hand.
B. Platinum does not react with oxygen at room temperature.
C. The page of the textbook is white.
D. The copper sheets that form the "skin" of the Statue of Liberty
have acquired a greenish coating over the years.
How many moles of iron are needed to react with 0.125 moles of oxygen
Given; 4Fe + 3O2 = 2Fe2O3
Answer:
0.167 mol Fe
Explanation:
4 Fe + 3 O₂ ⇒ 2 Fe₂O₃
Convert moles of oxygen to moles of iron using the mole ratio. You can find the mole ratio using the chemical equation. For every 4 moles of iron, you will need 3 moles of oxygen.
(0.125 mol O₂) (4 mol Fe/3 mol O₂) = 0.167 mol Fe
Answer:
Your mom says to stop cheating
Explanation:
Sodium carbonate (0.3379 g, FW: 105.99) was dissolved in deionized water to give a solution with a total volume of 250.0 mL. What was the pH of the resulting solution
Answer:
pH = 11.179
Explanation:
The sodium carbonate, Na2CO3, is in equilibrium with water as follows:
Na2CO3 + H2O ⇆ NaHCO3 + OH⁻
Where Kb is 1.786x10⁻⁴:
Kb = 1.786x10⁻⁴ = [NaHCO3] [OH-] / [Na2CO3]
Where [NaHCO3] = [OH-] = X, our incognite
And [Na2CO3] is molar concentration of sodium carbonate:
[Na2CO3] = 0.3379g * (1mol / 105.99g) = 3.188x10⁻³ moles Na2CO3
In 250.0mL = 0.2500L:
3.188x10⁻³ moles Na2CO3 / 0.2500L = 0.01275M
Replacing in Kb expression:
1.786x10⁻⁴ = [NaHCO3] [OH-] / [Na2CO3]
1.786x10⁻⁴ = [X] [X] / [0.01275]
2.278x10⁻⁶ = X²
X = [OH⁻] = 1.509x10⁻³M
As pOH = -log [OH⁻] = 2.821
And pH = 14 - pOH
pH = 11.179what element is found in gruop 6 and period 4
Name the monosaccharides that make up each of the
disaccharides and give a common food source of each disaccharide.
Answer:
Glucose. Fructose. Galactose.
Explanation:
Glucose +fructose=succrose(normal sugar)
Glucose+Glucose= Maltose(wheat sugar)
Glucose+Galactose= Lactose(milk sugar)
Are organs made of cells true or false
Answer:
true
Explanation:
An organ is made of several types of tissue and therefore several types of cells. For example, the heart contains muscle tissue that contracts to pump blood, fibrous tissue that makes up the heart valves, and special cells that maintain the rate and rhythm of heartbeats.
Answer:
True
Explanation:
Cells make up tissues, which makes up organs
Hope this helps! Good luck :)
What type of bonding around a central atom would result in a trigonal planar
molecule?
A. Three groups bound to it with no lone pairs
B. One group bound to it with two lone pairs
C. Three groups bound to it with one lone pair
D. Four groups bound to it with no lone pairs
Explanation:
A. 3 groups bound to it with no lone pairs
Which conclusion can be drawn from a cathode ray being deflected toward the positive plate?
A. Atoms are indivisible.
B. There is gas in the tube.
C. A magnetic field is produced.
D. The particles of the ray are negatively charged.
Answer:
D
Explanation:
The cathode rays are being deflected towards the positive plate because the particles of the ray are negatively charged
Explanation:
The cathode ray is a beam of electrons emerging from the negatively charged electrode (cathode) in a vacuum.They have a negative electric charge.Being negatively charged they are attracted by the positive charge.They possess the properties of a particle.They travel in a straight line, perpendicular to the cathode surface.They cause ionization of gas through which they pass.So, from this, we can conclude that the cathode rays are being deflected towards the positive plate because the particles of the ray are negatively charged.
Learn more about cathode rays here:
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After 0.050 mole of hydrofluoric acid is dissolved in 200 mL of aqueous solution, it is found that 7.90% of the acid is dissociated at equilibrium. Calculate the equilibrium concentrations of H3O , undissociated hydrofluoric acid (HF), and conjugate weak base of hydrofluoric acid.
Answer:
[HF] = 0.23M
0.02M = [F⁻]
[H₃O⁺] = 0.02M
Explanation:
The equilibrium of HF with water is:
HF + H₂O ⇄ H₃O⁺ + F⁻
Where F⁻ is the conjugate base of the HF
The initial concentration of HF is:
[HF] = 0.0500mol / 0.200L = 0.25M
Now, in equilibrium, if the 7.90% is dissociated, the undissociated HF is the 100 - 7.90 = 92.1%
0.25M*92.1% = 0.23M = [HF]
The conjugate base will be 0.25M - 0.23M = 0.02M = [F⁻]
And as the H₃O⁺ ion comes from the same equilibrium of F⁻ and is produced in the same proportion:
[H₃O⁺] = 0.02M
The muscles of the body are part of the musculoskeletal system but would not operate without the
impulses that cause the muscles to act.
A cardiovascular
B. respiratory
C nervous
D reproductive
Answer:
C
Explanation:
The nervous system sends signals, or in this case, impulses to parts of your body that direct them to move.
Which of the following molecules would be expected to have a trigonal planar geometry?
a
NH3
b
CH4
c
H2O
d
CH2O
Answer:
CH2O
Explanation:
According to the valence shell electron pair repulsion theory, electron pairs tend to position themselves as far apart in space as possible to minimize repulsion.
The shape of a molecule depends on the number of electron pairs present on the valence shell of the central atom in the molecule- both lone pairs and bond pairs.
CH2O has three electron domains. the possession of three electron domains and no lone pairs of electrons on the central atom corresponds to a trigonal planar geometry.
4. Which of the following is the most stable isotope?
Polonium-210
Uranium-237
Francium-227
Plutonium-238
Half-life
(hr)
3,310
162
0.04
768,000
A. Polonium-210
B. Uranium-237
C. Francium-227
D. Plutonium-238
D. Plutonium-238 is the most stable isotope
Further explanationRadioactivity is the process of unstable isotopes to stable isotopes by decay, by emitting certain particles (such as alpha (α), beta (β), gamma (γ) particles)
General formulas used in decay:
[tex]\large {\boxed {\bold {N_t = N_0 (\dfrac {1} {2}) ^ {t / t \frac {1} {2}}}}[/tex]
T = duration of decay
t 1/2 = half-life
N₀ = the number of initial radioactive atoms
Nt = the number of radioactive atoms left after decaying during T time
Half-life shows the time it takes for an atom to get half of its initial mass (to decay to half of its initial mass)
The longer the half-life indicates the stability of the atom
Half-life (hr) of isotopes :
Polonium-210 : 3,310
Uranium-237 : 162
Francium-227 : 0.04
Plutonium-238 : 768,000
The half-life value above shows that Plutonium-238 has the longest time, making it the most stable
PLEASE HELP ME!!!
Which of these is measured during a scientific investigation?
Group of answer choices
Test variable (independent variable)
Outcome variable (dependent variable)
Control group
Hypothesis
Answer:
Outcome Variable
Explanation:
Control group and Hypothesis are not what your measuring.
Test variable would be like- "amount of water added"
Outcome variable would be something like- "amount plants grew"
You would be measuring the amounts the plants grew, based on the water added.
Plants need to use the gas CARBON DIOXIDE for photosynthesis. true or false
What does this image represent?
Amine group
Carbonyl group
Ether group
Hydroxyl group
Previous Question
Answer:
Ether group.
Explanation:
Ethers are the compounds that connect two aryl or alkyl groups by an oxygen atom and represented by R–O–R′ where R either aryl or alkyl groups. Ether can be identified by the presence of alKyl groups on either side of the oxygen atom commonly. Diethyl ether, methyl ethyl ether are some of the examples of alkyl ether
Thus, the correct answer is - Ether group.
A sample of an ideal gas has a volume of 2.29 L at 285 K and 1.12 atm. Calculate the pressure when the volume is 1.33 L and the temperature is 302 K.
Answer:
[tex]P_2=2.04atm[/tex]
Explanation:
Hello.
In this case, by using the combined ideal gas law, we can identify the change in pressure, temperature an volume as shown below:
[tex]\frac{P_1V_1}{T_1} =\frac{P_2V_2}{T_2}[/tex]
In such a way, since we are asked to compute the final pressure, P2, we proceed as follows:
[tex]P_2=\frac{P_1V_1T_2}{T_1V_2} \\\\P_2=\frac{1.12atm*2.29L*302K}{285K*1.33L}\\ \\P_2=2.04atm[/tex]
Best regards!
which element has one electron in its fourth and outermost main energy level
Answer:K,Potassium
Explanation:
will gave a brain thingy. What are the conditions required for natural selection? Check all that apply.
overproduction of offspring
same traits among all organisms in a population
variation among organisms in a population
favorable adaptations selected by nature
unfavorable adaptations passed on to offspring in larger numbers
favorable adaptations building in population over time
Answer:
everything.
Explanation:
You need nice weather,good realation ships as well as convection
Answer:
A C D F
Explanation:
How many electrons can have the following quantum numbers in an atom: n =
3,1 = 2? Explain.
Give the complete ionic equation for the reaction that occurs when aqueous solutions of sodium sulfide and iron(II) nitrate are mixed.
Answer:
2 Na⁺(aq) + S²⁻(aq) + Fe²⁺(aq) + 2 NO₃⁻(aq) ⇒ FeS(s) + 2 Na⁺(aq) + 2 NO₃⁻(aq)
Explanation:
Let's consider the molecular equation that occurs when aqueous solutions of sodium sulfide and iron(II) nitrate are mixed.
Na₂S(aq) + Fe(NO₃)₂ ⇒ FeS(s) + 2 NaNO₃(aq)
The complete ionic equation includes all the ions and the species that do not dissociate in water.
2 Na⁺(aq) + S²⁻(aq) + Fe²⁺(aq) + 2 NO₃⁻(aq) ⇒ FeS(s) + 2 Na⁺(aq) + 2 NO₃⁻(aq)
The complete ionic equation for the reaction between aqueous solution of sodium sulfide and iron(II) nitrate is
2Na⁺(aq) + S²⁻(aq) + Fe²⁺(aq) + 2NO₃⁻(aq) —> FeS(s) + 2Na⁺(aq) + 2NO₃⁻(aq)
The complete ionic equation for the reaction between aqueous solution of sodium sulfide and iron(II) nitrate can be written as follow:
In solution, Na₂S and Fe(NO₃)₂ will dissociate as follow:
Na₂S(aq) —> 2Na⁺(aq) + S²¯(aq)
Fe(NO₃)₂(aq) —> Fe²⁺(aq) + 2NO₃¯(aq)
The reaction will proceeds as illustrated below to give the complete ionic equation:
Na₂S(aq) + Fe(NO₃)₂(aq)—>
2Na⁺(aq) + S²¯(aq) + Fe²⁺(aq) + 2NO₃¯(aq) —> FeS(s) + 2Na⁺(aq) + 2NO₃¯(aq)
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What volume (in mL) of a 0.341 M HCl solution is needed to neutralize 43.9 mL of a 0.480 M NaOH solution
Answer:
61.8 mL
Explanation:
We'll begin by writing the balanced equation for the reaction. This is illustrated below:
HCl + NaOH —> NaCl + H2O
From the balanced equation above,
Mole ratio of the acid (nA) = 1
Mole ratio of the base (nB) = 1
Next, the data obtained from the question include:
Molarity of acid, HCl (M1) = 0.341 M
Volume of base, NaOH (Vb) = 43.9 mL
Molarity of base, NaOH (Mb) = 0.480 M
Volume of acid, HCl (Va) =?
The volume of the acid needed for the reaction can be obtained as follow:
MaVa/MbVb = nA/nB
0.341 × Va / 0.480 × 43.9 = 1/1
Cross multiply
0.341 × Va × 1 = 0.480 × 43.9 × 1
0.341 × Va = 21.072
Divide both side by 0.341
Va = 21.072 /0.341
Va = 61.8 mL
Therefore, 61.8 mL of the acid, HCl is needed for the reaction.
Compound 1 melts at 50°C. Compound 2 melts at 210°C. Compound 3 melts at 1240°C. Compound 4 melts at -62°C. Which is most likely to
be an ionic compound?
A. Compound 1
B. Compound 2
C. Compound 3
D. Compound 4
A 1 liter solution contains 0.384 M acetic acid and 0.512 M sodium acetate. Addition of 0.422 moles of calcium hydroxide will:
Answer:
- Exceed the buffer capacity
- Raise the pH by several units
Explanation:
Will:
(Assume that the volume does not change upon the addition of hydrobromic acid.)
Raise the pH slightly
Lower the pH slightly
Raise the pH by several units
Lower the pH by several units
Not change the pH
Exceed the buffer capacity
1L of a buffer of 0.384M acetic acid and 0.512M of sodium acetate contains 0.384 moles of the acid and 0.512 moles of the salt.
A base as Ca(OH)2 reacts with the acid, CH3COOH as follows:
Ca(OH)2 + 2CH3COOH → Ca(CH3COO)₂ + 2 H2O
For the reaction of the 0.422 moles of calcium hydroxide are required:
0.422 moles Ca(OH)2 * (2 moles CH3COOH / 1 mole Ca(OH)2) = 0.844 moles of CH3COOH
As there are just 0.384 moles of acetic acid:
Exceed the buffer capacity
And:
Raise the pH by several units
-Because the solution becomes more basic-
Round the following number to 4 significant figures... 11278.30 *
1 point
11280
1128
11278
78.30
Answer:
11280
Explanation:
Given that the molar mass of the Red 40 dye is equal to 496.42 g/mol, how many grams of Red 40 food dye were in the 0.235 L solution of drink mix
Answer:
5.21 g
Explanation:
Density of Red 40 = molar mass/molar volume
since the molar volume = 22.4 L
Density of Red 40 = 496.42 g/mol/22.4 L
Density of 496.42 g/mol = 22.16 g/L
But;
density = mass/volume
volume of Red 40 = 0.235 L
mass = density * volume
mass = 22.16 g/L * 0.235 L
mass = 5.21 g
The mass of the red 40 dye in the 0.235 L solution is 5.21 g
We'll begin by calculating the density of the red 40 dye. This can be obtained as follow:Molar mass of red 40 dye = 496.42 g/mol
Molar volume = 22.4 L
Density =?[tex]Density = \frac{mass}{volume}\\\\ = \frac{496.42}{22.4}\\\\[/tex]
Density of red 40 dye = 22.16 g/L
Finally, we shall determine the mass of the red 40 dye in the solution. This can be obtained as follow:Density of red 40 dye = 22.16 g/L
Volume = 0.235 L
Mass of red 40 dye =?
Mass = Density × Volume
= 22.16 × 0.235
Mass of red 40 dye = 5.21 g
Therefore, the mass of the red 40 dye in the solution is 5.21 g
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A sample of air has a volume of 140.0 mL at 67°C.
At what temperature would its volume be 50.0 mL at
constant pressure?
Answer:
about 121.5 K or -151.7 °C
Explanation:
Volume of an ideal gas is proportional to the absolute temperature. At 67 °C, the absolute temperature is 67+273.15 K, or 340.15 K.
Then 50.0/140.0 times that temperature is ...
(5/14)(340.15 K) ≈ 121.482 K ≈ -151.668 °C
The volume would be 50.0 mL at a temperature of about 121.5 K or -151.7 °C.