Sorry heres the one in the last question

When the concentration of A in the reaction A ..... B was changed from 1.20 M to 0.60 M, the half-life increased from 2.0 min to

Reika [66]

Answer:

2

$0.4167\ \text{M}^{-1}\text{min}^{-1}$

Explanation:

Half-life

${t_{1/2}}A=2\ \text{min}$

${t_{1/2}}B=4\ \text{min}$

Concentration

${[A]_0}_A=1.2\ \text{M}$

${[A]_0}_B=0.6\ \text{M}$

We have the relation

$t_{1/2}\propto \dfrac{1}{[A]_0^{n-1}}$

So

$\dfrac{{t_{1/2}}_A}{{t_{1/2}}_B}=\left(\dfrac{{[A]_0}_B}{{[A]_0}_A}\right)^{n-1}\\\Rightarrow \dfrac{2}{4}=\left(\dfrac{0.6}{1.2}\right)^{n-1}\\\Rightarrow \dfrac{1}{2}=\left(\dfrac{1}{2}\right)^{n-1}$

Comparing the exponents we get

$1=n-1\\\Rightarrow n=2$

The order of the reaction is 2.

$t_{1/2}=\dfrac{1}{k[A]_0^{n-1}}\\\Rightarrow k=\dfrac{1}{t_{1/2}[A]_0^{n-1}}\\\Rightarrow k=\dfrac{1}{2\times 1.2^{2-1}}\\\Rightarrow k=0.4167\ \text{M}^{-1}\text{min}^{-1}$

The rate constant is $0.4167\ \text{M}^{-1}\text{min}^{-1}$

3 0

2 years ago

Help please thanks you

scoundrel [369]

Explanation:

Ok so water is H2O and cabon dioxide in the air is CO2, so the water goes through the carbon dioxide and makes acid rain H2SO4.

Now we have our limestone which is CaCO3.

What happens is that the acid breaks apart our limestone into Ca2+ and CO3 2-. This then reforms into Calcium bicarbonate Ca(CO3)2.

Calcium bicarbonate is soluble in water and is hence washed away by the rain eroding the limestone.

5 0

2 years ago

To launch a rocket, liquid oxygen and liquid hydrogen are combined inside the rocket engine to react explosively. How do you thi

KIM [24]

Answer:

Explanation:

In this chemistry lab, students investigate how to build and launch a simple rocket that uses hydrogen and oxygen gases that will be mixed to propel the rocket (large bulb plastic pipette). Students will understand the principles of combustion reactions, kinetics, stoichiometry of reactions, activation energy, explosive mixtures, rocketry, and different types of chemical reactions. Students will explore and determine the proportions of hydrogen and oxygen mixture that will achieve the best launch results. Students will compare the balanced chemical reaction of hydrogen and oxygen with their lab results; students should discover that the optimal distance occurs when the mixture of hydrogen and oxygen is two to one hydrogen, oxygen mixture ratio and this can be determined theoretically from the balanced chemical reaction equation. Students will perform the lab, collect data, and discuss, compare, and contrast their lab findings with the balanced chemical reaction equation. Students will present their structured inquiry investigations using a power-point presentation. Other groups along with the teacher will assess each group by using a provided rubric. Group assessments will be the deciding assessment for the final lab score. A follow up activity could investigate how NASA scientists launch real rockets into space and propose a procedure to investigate and collect data on a launching a heavier object at the school football field.

3 0

2 years ago

Common table salt is sodium chloride. when table salt is dissolved in water, the solution conducts electricity because

enot [183]

<span>In commonly table salt is sodium chloride. When table salt is dissolved in water, the solution conducts electricity because sodium chloride is made up of ions, it is called an ionic substance.</span>

4 0

3 years ago

The rate of effusion of an unknown gas was measured and found to be 11.9 mL/min. Under identical conditions, the rate of effusio

iren2701 [21]

Answer : The correct option is, (B) $CO_2$