Calculate the pH of the buffer that results from mixing 60.0 mL of 0.25 M HCHO2(pKa= 3.74) and 15.0 mL of 0.500 M NaCHO
Answer:
[tex]pH=3.44[/tex]
Explanation:
Hello.
In this case, since the formic acid (HCHO2) is a weak acid and it is mixed with its conjugate base (CHO2⁻) in the form of NaCHO2, we can compute the pH via the Henderson-Hasselbach equation:
[tex]pH=pKa+log(\frac{[Base]}{[Acid]} )[/tex]
Whereas the concentration of both acid and base are computed considering final total volume of 75.0 mL after adding the volume of each solution as shown below:
[tex]n_{base}=0.500mol/L*0.0150L=7.50x10^{-3}mol\\\\n_{acid}=0.25mol/L*0.0600L=1.5x10^{-2}mol[/tex]
And the resulting concentrations upon the final volume:
[tex][Base]=\frac{7.50x10^{-3}mol}{0.0750L}=0.1M[/tex]
[tex][Acid]=\frac{1.5x10^{-2}mol}{0.0750L}=0.20M[/tex]
Thus, the pH is:
[tex]pH=3.74+log(\frac{0.10M}{0.20M} )\\\\pH=3.44[/tex]
Best regards.
A runner has a mass of 60 kg and a velocity of 0 m/s. What is her momentum?
Answer:
The answer is 0 kg m/sExplanation:
The momentum of an object can be found by using the formula
momentum = mass × velocity
From the question the momentum of the runner will be 0 kgm/s since the runner's velocity is 0
Hope this helps you
how many molecules are there in 24 grams of FeF3
Answer:
1.2x1023 molecules
hope this helped!
Explanation:
1227.6
Which element is a nonmetallic liquid at room
temperature?
(1) hydrogen
(2) oxygen
(3) mercury
(4) bromine
Answer:
According to my research there are 2 answers present.
Explanation:
Bromine as well as mercury is a nonmetallic liquid at room temperature
Why is it important to keep your fingers and hands away from your face while cooking?
Answer:
To prevent the spread of germs.
Explanation:
The shark and remora have a relationship that benefits the remora but neither helps nor harms the shark What type of relationship is this
Give the hybridization for the C in HCN. Give the hybridization for the C in HCN. sp3d2 sp3 sp2 sp sp3d
Answer:
The correct answer is - sp hybridization.
Explanation:
The molecular structure line with a carbon bound to the hydrogen with the single sigma bond and with 2 pi bond and one single sigma bond with carbon Nitrogen triple covalent bond.
To calculate the hybridization of an element like carbon by adding the sigma bond and the lone pair of that atom as here in HCN molecule, zero lone electrons and two sigmas bond the C atom includes sp-hybridized orbital.
The hybridization for the carbon (C) atom in HCN (hydrogen cyanide) is sp. Therefore, option D is correct.
The electron configuration of carbon is 1s² 2s² 2p², with four valence electrons. In HCN, carbon forms three sigma bonds: one with hydrogen (H) and two with nitrogen (N). The sigma bonds are formed by overlapping atomic orbitals.
In the process of hybridization, the carbon atom promotes one of its 2s electrons to a 2p orbital to create a set of four hybrid orbitals. In HCN, only three hybrid orbitals are involved in bonding. One sp hybrid orbital of carbon overlaps with the 1s orbital of hydrogen to form the C-H sigma bond. The other two sp hybrid orbitals of carbon overlap with two nitrogen atoms, forming the C-N sigma bonds.
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The major advantage of using ground glassware ( round bottom flask, distillation condenser, thermometer adapter, separatory funnel) in the organic lab is
Answer:
The major advantage of using ground glassware in the organic chemistry laboratory is that the joints can quickly and easily fit to other apparatus so that various reactions can be conducted from these various assembling of apparatuses.
Explanation:
Ground glass is glass whose polished surface has been ground to produce a rough finish.
Most organic chemistry laboratory glasswares are designed with ground glass joints. The joints are leak-tight and have outer (female) and inner (male) joints that can be tightly connected together.
These glassware are very important in the organic chemistry laboratory because they can be assembled and disassembled for various reactions conducted in the laboratory without having to have a specific custom-made glassware for each reaction or synthesis process performed in the laboratory. For example, a Liebig condenser can be used for various distillation reactions in the laboratory due to its joint that can be fitted to other apparatus in these reactions.
Also, ground glassware joints are chemical resistant and heat resistant unlike corks or rubber bungs and glass tubes.
Kemmi Major weights 153.0 g of ammonium chloride (NH4Cl) salt. She also weighs 500.0 g of DI water. She combines the salt and the water to make her solution. Calculate the molality of the NH4Cl solution. Answer to 4 significant figures with appropriate units.
Answer:
5.720 m
Explanation:
Step 1: Given data
Mass of ammonium chloride (solute): 153.0 gMass of DI water (solvent): 500.0 gStep 2: Calculate the moles of solute
The molar mass of ammonium chloride is 53.49 g/mol.
153.0 g × (1 mol/53.49 g) = 2.860 mol
Step 3: Calculate the kilograms of solvent
We will use the relationship 1 kg = 1000 g.
500.0 g × (1 kg/1000 g) = 0.5000 kg
Step 4: Calculate the molality of the solution
m = 2.860 mol / 0.5000 kg = 5.720 m
How many valence electrons must a potassium atom lose to obtain a complete valence shell?
two
three
one
four
Identify the reducing agent. 2 Al3+(aq) + 2 Fe(s) → 2 Al(s) + 3 Fe2+(aq)
Answer:
Al = Reduced (Oxidizing agent)
Fe = Oxidized (Reducing agent)
Explanation:
Al became less positive meaning that it gained an electron and Fe became more positive meaning that it lost elections. remember OIL RIG. Oxidation in loss of electrons and Reduction involves gain of electrons
Answer: The answer would be Fe.
Explanation: As "Fe" loses electrons, it becomes the reducing agent.
Solid calcium reacts with solid sulfur to produce solid calcium sulfide?
Answer:
Ca + S -----> CaS
Explanation:
Since it is balanced you don't need to multiply it any more.
Solid calcium reacts with solid sulfur to produce solid calcium sulfide. The balanced equation for this reaction can be given as Ca + S → CaS.
What is balanced equation?An equation for just a chemical reaction is said to be balanced if both the reactants as well as the products have the same number of atoms and total charge for each component of the reaction. In other words, both sides of a reaction have an equal balance of mass and charge.
The ingredients and outcomes of a chemical reaction are listed in an imbalanced chemical equation, but the amounts necessary to meet the conservation of mass are not specified. Solid calcium reacts with solid sulfur to produce solid calcium sulfide. The balanced equation for this reaction can be given as Ca + S → CaS.
Therefore, the balanced equation for this reaction can be given as Ca + S → CaS.
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During which change of state do atoms lose energy?
A. sublimation
B. freezing
C. boiling
D. melting
Answer:
B. freezing
Explanation:
During freezing, atoms lose energy. In this process, the molecules lose heat energy and they cool down. This reduces randomness of the matter.
In sublimation, heat is added to a matter, the molecules are agitated and their entropy increases. Boiling and melting are similar in that these processes heat is supplied. Then the particles are agitated and the molecules will tend to move apart more rapidly.Answer:
B)Freezing
Explanation:
just took the test edge 2021
which diagram best represents the type of plate movement that results in the mountains
Answer:
I think it’s D.
Explanation:
In a chemical reaction, two reactants mix. The resulting substance is called a(n) ________. A ionic bond B atomic bond C product D transitional metal
Answer:
product
Explanation:
Chemical reactions are said to be the formation of the products from the reactants. "In a chemical reaction, two reactants mix. The resulting substance is called a product." Thus, option C is correct.
What is a chemical reaction?A chemical reaction has been defined as the rearrangement of the atoms of the reactant molecules to result in new substances that differ in chemical properties and compositions. This results in the chemical transformation that results in product formation.
The products produced are new substances that are formed by the breaking or the combination of two or more reactants. The molecules of the reactant undergo collision that forms or breaks the bonds of the reactants.
The products produced are different in chemical properties and composition from the reactants it undergoes chemical changes. An example is iron rust, here iron undergoes oxidation to produce rust that is irreversible changes.
Therefore, option C. product is formed by mixing two or more reactants in a chemical reaction.
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Sunlight that reaches the earth is transformed into chemical energy in the form of
water
oxygen
carbon dioxide
sugar
Answer:
oxygen
Explanation:
I dont know if you still need it but here it is
How many hours will it take to fill a cubic vat of 18.7 fit edge length that has a density of 1.49 g/mL and is spilling at a rate of 3.85kg/s?
Answer:
It will take 19.9 hours to fill the cubic.
Explanation:
First, we can find the volume of the cubic.
[tex]V_{c}=18.7^{3}ft^{3}=6539.2 ft^{3}=1.85*10^{8} ml[/tex]
Let's multiple this volume times the density
[tex]V_{c}*\rho=1.85*10^{8} ml * 1.49 g/ml = 2.76*10^{8} g[/tex]
If we divide the spilling rate by V times density we will have:
[tex]t=\frac{V_{c}}{\rho R}=2.76*10^{5} kg/3.85kg/s=71688.3 s = 19.9 h[/tex]
Therefore, it will take 19.9 hours to fill the cubic.
I hope it helps you!
The study of chemicals and bonds is called chemistry. when the amount reactant and the product is equal is said to be equilibrium.
The correct answer is 19.9h.
What is density?The density, of a substance is its mass per unit volume.The formula used to solve the question is as follows:-
[tex]D= \frac{M}{V}[/tex]
The data is given as follows:-
[tex]V = 1.85*10^8\\[/tex]The density of the is as follows:-
[tex]V*D =1.85*10^8 *1.49 =2.76*10^8[/tex]
Hence, the time will be as follows:-
[tex]t=\frac{V_c}{Dr}\\ \\=\frac{2.76*10^5}{3.85} \\ = 71688.3s\\=19.9h[/tex]
Hence, the correct time is 19.9h.
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Use the balanced chemical equation to calculate the grams of HF that need to react with 4.44 g of SnF2. Express the mass in grams to three significant figures.
Answer:
Explanation:
SnF₂ + 2HF = H₂Sn + 4F
mol weight of SnF₂ = 156.7
mol weight of HF = 20
156.7 gram of SnF₂ reacts with 40 grams of HF
4.44 gram of SnF₂ reacts with 40 x 4.44 / 156.7 grams of HF
= 1.13 grams of HF .
can someone please help me it's already past due
Answer:
Q1: 4
Q2: 2
Q3: 2
Explanation:
A solution of potassium sulfide is mixed with a solution of magnesium bromide. Identify the two possible products.
A. MgBr
B. KS
C. K2S
D. K2Br2
E. MgBr2
F. MgS
G. KBr
Write the formula of the insoluble product from part 1. 8 KBr.
Answer:
G. KBr
F. MgS
MgS is the insoluble product.
Explanation:
When 2 salts as potasium sulfide, K₂S and magnesium bromide, MgBr₂ react, a double replacement reaction occurs where cations (K⁺ and Mg²⁺) exchange places, as follows:
K₂S + MgBr₂ → 2 KBr + MgS
Thus, the two possible products are:
G. KBr
F. MgS
Now, based on solubility rules:
All compounds containing alkali metal ions (As K⁺) are solubles in water. KBr is soluble
And all sulfides except calcium, strontium and barium sulfide are insoluble.
Thus, the insoluble product is:
MgS
Which theory describes the way atoms are arranged within a molecule?
A. The scientific theory
B. The VSEPR theory
C. The Bohr atomic model
D. The atomic theory
Answer:
B. The VSEPR theory
Explanation:
The valence shell electron pair repulsion theory describes the way in which atoms are arranged within a molecule.
If an atom is bonded to two or more other kinds of atoms as in many covalent molecules and ions, the shape of the system is determined by the geometry of the bonds around the central atom. The variations in the bond angles of such molecules and ions can be explained by the valence shell electron pair repulsion model and hybridization. All electron pairs will orient themselves in such a way as to minimize the electrostatic repulsion between them.Answer:
B
Explanation:
The VSEPR theory
During photosynthesis, plants produce "food" for themselves. When animals eat plants, they take in energy that originally came from?
A.A seed
B. the soil
C. water
D. the sun
When solid sodium hydroxide (NaOH) pellets are dissolved in water, the temperature of the water and beaker rises. This is an example of ________
Answer:
Exothermic Reaction
Explanation:
The increase in temperature is as a result of the release of energy due to the dissolving of the NaOH pellets in water. This is an example of exothermic reactions.
They are easy to identify as the surroundings of the system becomes hot due to the release of the energy.
Predict the charge of the most stable ion of sodium
Imagine an element that has 15 protons, 16 neutrons, and 18 electrons. Which of the following would NOT be considered an isotope of this element? *
15 protons, 16 neutrons, and 15 electrons
15 protons, 17 neutrons, and 15 electrons
15 protons, 15 neutrons, and 18 electrons
Answer:
A: 15 protons, 16 neutrons, and 15 electrons
Explanation: An isotope of an element is when neutrons are taken away from the nucleus, or added to the nucleus.
If you change the amount of protons in the nucleus, not only will the charge become positive due to their being one more proton than an electron, but the atom will change to a new element, Sulfur. If you change the electron count, that will just affect how prominent the negative charge is on the atom, whether it be more negative by adding an electron, or more postitive by removing an electron. Therefore, the amount of neutrons that you add to the nucleus of an atom, will change the isotope of the atom, and that's why the answer is A because every other answer changes the neutron count other than A.
True or False: Secondary succession occurred in The Lorax
Answer:
true
Explanation:
the way the place grew back to life my g
Answer:
True
Explanation:
Secondary succession is when a terrain grows again after it's been destroyed.
Which solution contains the fewest total ions?
400. mL of 0.10 M NaCl
300. mL of 0.10 M CaCl2
200. mL of 0.10 M FeCl3
800. mL of 0.10 M C4H10
Silicon has three naturally occurring isotopes. Based on the AVERAGE atomic mass, which is 28.085, what is the likely mass of the most common isotope
26
27
28
29
30
The most common isotope : Si-28, ²⁸Si
Further explanationThe elements in nature have several types of isotopes
Isotopes are elements that have the same Atomic Number (Proton)
Atomic mass is the average atomic mass of all its isotopes
In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu
An atomic mass unit = amu is a relative atomic mass of 1/12 the mass of an atom of carbon-12.
The 'amu' unit has now been replaced with a unit of 'u' only
Mass atom X = mass isotope 1 . % + mass isotope 2.% ..
The most common isotope is an isotope with a very large percentage which is indicated by the mass number closest to the average atomic mass
So from the above isotopes that are close to their average mass number is the Si-28
What is the half-life of radon-222 if a sample initially contains 120.0 mg and only 18.1 mg after 12.3 days?
Answer:
[tex]t_{1/2}=4.51days[/tex]
Explanation:
Hello.
In this case, since the kinetics of radioactive decay in terms of initial and final amounts, elapsed time and half-life is:
[tex]A=A_0\times2^{-t/t_{1/2}}[/tex]
we can compute the half time as shown below:
[tex]2^{-t/t_{1/2}}=\frac{A}{A_0}\\\\-\frac{t}{t_{1/2}} ln(2)=ln(\frac{A}{A_0})\\\\t_{1/2}=-\frac{t\times ln(2)}{ln(\frac{A}{A_0})}[/tex]
Plugging in the known amounts and elapsed time, we obtain:
[tex]t_{1/2}=-\frac{12.3\times ln(2)}{ln(\frac{18.1}{120})}\\\\t_{1/2}=4.51days[/tex]
Best regards!
name the gas that is largely responsible for the acid rain phenomena
Answer:
sulfur dioxide
Explanation: