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3 years ago

Which of the following is necessary to do a complete stoichiometric calculation? A) Add the nuclear masses of the products.

Chemistry

1 answer:

Katena32 [7]3 years ago

5 0

Answer:

Option (C). Write the complete balanced chemical equation.

Explanation:

Writing a balanced chemical equation is the key to arriving at the correct stoichiometric calculations because it gives a fore knowledge of the correct amount of reactants needed to generate a predicted products for a given reaction

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The bromination of acetone is acid-catalyzed.CH3COCH3 + Br2 CH3COCH2Br + H+ + Br -The rate of disappearance of bromine was measu

Ann [662]

Answer:

a) The rate law is:

rate = k[Acetone][Br₂]⁰[H⁺] = k[Acetone][H⁺]

b) The value of k is:

k = 3.86 × 10⁻³ M⁻¹ · s⁻¹

Explanation:

Acetone (M) Br2 (M) H+ (M) Rate (M/s)

0.30 0.050 0.050 5.7 x 10-5

0.30 0.10 0.050 5.7 x 10-5

0.30 0.050 0.10 1.2 x 10-4

0.40 0.050 0.20 3.1 x 10-4

0.40 0.050 0.050 7.6 x 10-5

A generic rate law for this reaction could be written as follows:

rate = k[Acetone]ᵃ[Br₂]ᵇ[H⁺]ⁿ

The rate for the reaction in trial 2 is:

rate 2 = 5.7 ×10⁻⁵M/s = k(0.3)ᵃ(0.1)ᵇ(0.050)ⁿ

For the reaction in trial 1:

rate 1 = 5.7 ×10⁻⁵M/s = k(0.3)ᵃ(0.050)ᵇ(0.050)ⁿ

If we divide both expressions, we can obtain "b": rate2 / rate1:

rate2/rate1 = k(0.3)ᵃ(0.1)ᵇ(0.050)ⁿ / k(0.3)ᵃ(0.050)ᵇ(0.050)ⁿ

1 = 2ᵇ

b = 0

If we now take the expressions from trial 3 and 1 and divide them, we can obtain "n":

rate 3/rate 1 = k(0.3)ᵃ(0.050)⁰(0.01)ⁿ/ k(0.3)ᵃ(0.050)⁰(0.050)ⁿ

2.1 = 2ⁿ Applying ln to both side of the equation:

ln 2.1 = n ln2

ln2.1/ln2 = n

1 ≅ n

Taking now the reaction in trial 5 and 1 and dividing them:

rate 5/rate 1 = k(0.4)ᵃ(0.050)⁰(0.050) / k(0.3)ᵃ(0.050)⁰(0.050)

4/3 = 4/3ᵃ

a = 1

a)Then the rate law can be written as follows:

rate = k[Acetone][Br₂]⁰[H⁺]

It might be suprising that the rate of bromination of acetone does not depend on the concentration of Br₂. However, looking at the reaction mechanism, you can find out why.

b) Now, we can find the constant k for every experiment and calculate its average value:

rate / [Acetone][Br₂]⁰[H⁺] = k

For reaction 1:

k1 = 5.7 ×10⁻⁵M/s / (0.3 M)(0.050 M) = 3.8 ×10⁻³ M⁻¹ · s⁻¹

Reaction 2: k2 = 5.7 ×10⁻⁵M/s / (0.30 M)(0.050 M) = 3.8 ×10⁻³ M⁻¹ · s⁻¹

Reaction 3: k3 = 1.2 ×10⁻⁴M/s / (0.30 M)(0.10 M) = 4.0 ×10⁻³ M⁻¹ · s⁻¹

Reaction 4: k4 = 3.1 ×10⁻⁴M/s / (0.40 M)(0.20 M) = 3.9 ×10⁻³ M⁻¹ · s⁻¹

Reaction 5: k5 = 7.6 ×10⁻⁵M/s / (0.4 M)(0.05 M) = 3.8 ×10⁻³ M⁻¹ · s⁻¹

Averge value of k:

k = (k1 + k2 + k3 + k4 + k5)/5 = 3.86 × 10⁻³ M⁻¹ · s⁻¹

3 0

3 years ago

What is the maximum mass of s8 that can be produced by combining 89.0 g of each reactant?

lidiya [134]

Answer : We can produce 125.7 g of $S_{8}$ .

Explanation : The reaction will be

$8SO_{2} + 16H_{2}S -----> 3S_{8} + 16H_{2}O$

The molecular mass of $SO_{2}$ is 64.1 g/mol

and molecular mass of $H_{2}S$ is 34.1 g/mol

For every mole of $SO_{2}$ we would need twice of $H_{2}S$ moles, so for every 3 moles of $S_{8}$ we need 16 moles of $H_{2}S$

Now, we can calculate number of moles $S_{8}$

2.61 X (3/16) = 0.49 moles

Here, the molecular mass of $S_{8}$ is 256.8 g

multiplying it with the number of 0.49 moles we get, 256.8 X 0.49 = 125.7 g of $S_{8}$ .

Hence, 125.7 g of $S_{8}$ will be produced.

8 0

3 years ago

Why are facts and data important to science?

lara31 [8.8K]

Answer:

to bring more technology

3 0

3 years ago

Which statements best describes a major difference types of elements

Sever21 [200]

Answer:

The atoms of different elements have different numbers of protons and electrons.

6 0

3 years ago

Which shows the rational expression written using the least common denominator?

Alexandra [31]

Answer:

The first one.

$\frac{x + 1}{4x^{2} } and \frac{4(x + 1)}{4x^{2} }$

Explanation:

When comparing two fractions with variables like this, it's important to get to the same denominator in order to compare apples with apples and then be able to do not only comparisons but also perform additions/subtractions.

Question is which denominator to use and how to reach it.

In this case, the question and the answer choices do the work for you. The question asks which one is the LEAST common denominator, and the answers show denominators x² and 4x². The smallest of these is x², however, we can't simplify the first fraction to get to the x² denominator, so we'll go for the 4x².

So, the first fraction has already the correct denominator (4x²), we just have to transform the second one.

We multiply it by 1, expressed in a different way. Since we're multiplying by one, we're not affecting the value, just the way it looks.

Let's do it!, to get the denominator to go from x² to 4x², we need to multiply it by 4... so we'll multiply by 4/4 (which is 1, neutral for the multiplication).

$\frac{x + 1}{x^{2} } * \frac{4}{4} = \frac{4(x + 1)}{4x^{2} }$

And now you have both fractions on the same denominator, without having changed their value, just their looks

6 0

3 years ago