Which element glows red when electricity flows through it?

The reaction A + 2B → products was found to follow the rate law: rate = k[A] 2[B]. Predict by what factor the rate of reaction w

Alexus [3.1K]

Answer:

By a factor of 12

Explanation:

For the reaction;

A + 2B → products

The rate law is;

rate = k[A]²[B]

As you can see, the rate is proportional to the square of the concentration of A and the of the concentration of B .

Let's say initially, [A] = x, [B] = y

The rate law in this case is equal to;

rate1 = k. x².y

Now you double the concentration of A and triple the concentration of B.

[A] = 2x, [B] = 3y

The new rate law is given as;

rate2 = k . (2x)². (3y)

rate2 = k . 4x² . 3y

rate2 = 12 k . x² . y

Comparing rate 2 and rate 1, the ratio is given as; rate 2/ rate 1 = 12

Therefore the rate has increased by a factor of 12.

5 0

3 years ago

Read the following chemical equation.

AnnyKZ [126]

The correct fraction is 2/2.

The balanced equation is

2Al + 3Cl₂ → 2AlCl₃

x mol AlCl₃ × (2 mol Al/2 mol AlCl₃) = x mol Al

The molar ratio is 2 mol Al/2 mol AlCl₃, so the fraction is 2/2.

5 0

3 years ago

A solution is initially 0.10m in mg2+(aq) and 0.10m in fe2+(aq). solid naoh is slowly added. what is the concentration of fe2+ w

dexar [7]

Mg(OH)₂ ⇄ Mg²⁺ + 2 OH⁻

Ksp = [Mg²⁺] [OH⁻]²

6.0 x 10⁻¹⁰ = 0.10 x [OH⁻]²

[OH⁻] = 7.746 x 10⁻⁵ M

when Mg(OH)₂ 1st precipitates, [OH⁻] = 7.746 * 10⁻⁵ M

Fe(OH)₂ <—> Fe²⁺ + 2OH⁻

Ksp = [Fe²⁺] [OH⁻]²

7.9 x 10⁻¹⁶ = [Fe²⁺] x (7.746 x 10⁻⁵)²

[Fe²⁺] = 1.32 x 10⁻⁷ M

Answer: 1.32 x 10⁻⁷ M

5 0

3 years ago

A sample of 7.90 L of NH3 (ammonia) gas at 22 ∘C and 735 torr is bubbled into a 0.450 L solution of 0.400 M HCl (hydrochloric ac

lyudmila [28]

Answer: The pH of the solution is 9.14

Explanation:

For ammonia:

To calculate the amount of hydrogen gas collected, we use the equation given by ideal gas which follows:

$PV=nRT$

where,

P = pressure of the gas = 735 torr

V = Volume of the gas = 7.90 L

T = Temperature of the gas = $22^oC=[22+273]K=295K$

R = Gas constant = $62.364\text{ L. torr }mol^{-1}K^{-1}$

n = number of moles of ammonia = ?

Putting values in above equation, we get:

$735torr\times 7.90L=n\times 62.364\text{ L. torr }mol^{-1}K^{-1}\times 295K\\\\n=\frac{735\times 7.90}{62.364\times 295}=0.316mol$

For hydrochloric acid:

To calculate the number of moles for given molarity, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}$

Molarity of hydrochloric acid = 0.400 M

Volume of solution = 0.450 L

Putting values in above equation, we get:

$0.400M=\frac{\text{Moles of hydrochloric acid}}{0.450L}\\\\\text{Moles of hydrochloric acid}=(0.400\times 0.450)=0.18mol$

The chemical reaction for ethylamine and HCl follows the equation:

$NH_3+HCl\rightarrow NH_4Cl$

Initial: 0.316 0.18

Final: 0.136 - 0.18

Volume of the solution = 0.450 L

To calculate the pOH of basic buffer, we use the equation given by Henderson Hasselbalch:

$pOH=pK_b+\log(\frac{[salt]}{[base]})$

$pOH=pK_b+\log(\frac{[NH_4Cl]}{[NH_3]})$

We are given:

$pK_b$ = negative logarithm of base dissociation constant of ammonia = $-\log(1.8\times 10^{-5})=4.74$

$[NH_4Cl]=\frac{0.18}{0.450}$

$[NH_3]=\frac{0.136}{0.450}$

pOH = ?

Putting values in above equation, we get:

$pOH=4.74+\log(\frac{0.18/0.450}{0.136/0.450})\\\\pOH=4.86$

To calculate pH of the solution, we use the equation:

$pH+pOH=14\\pH=14-4.86=9.14$

Hence, the pH of the solution is 9.14

4 0

3 years ago

Which of the following characteristics of a watershed would act to reduce erosion?

Talja [164]

A large number of lakes

3 0

3 years ago