Semester TWO Chemistry TWO Review

Hydrazine, N2H4, is formed through the reaction below:

2H2(g) + N2(g) --> N2H4(l) Δ𝐻∘=+50.63𝑘𝐽/𝑚𝑜𝑙

Calculate the standard enthalpy change when 0.452 moles of N2H4 is formed at 1 atm and 298 K.

• 22.9

• 11.5

• 229

• None of the above

Tags

NGSS.HS-PS1-4

NGSS.HS-PS3-1

What is the pH of a solution with a pOH of 6.410?

***Use three sig figs***

Which of these aqueous solutions is a strong electrolyte: H2CO3 , HClO2, HNO3, HC2H3O2

• H2CO3

• HClO2

• HNO3

• HC2H3O2

Identify which of the following is a strong acid.

• HClO4

• K+

• Sr(OH)2

• None of the above

What is the molarity of the H3O+ ions in a solution with a pH of 3.869?

***Only use one sig fig***

• 0.0002

• 4

• 2

• 2000

• None of the above

If your overall rate law in an experiment is found to be:

Rate= k [A]2 [B] [C]

What is the overall reaction order?

• second

• third

• first

• none of the above

Tags

NGSS.HS-PS1-5

Given the reaction: 2N + B --> C with the rate law:

Rate= k [A]0 [B]2

When the concentration of A and B were 0.023M and 0.054 M, the reaction rate was 8.31*10^-2 M/sec, calculate the value for k.

• 4

• 28

• 0.0009

• 9000

Tags

NGSS.HS-PS1-5

The rate law for the decomposition of dinitrogen pentaoxide (shown below) is experimentally determined to be rate=k[N2O5]. A student claims that this reaction occurs in a one-step mechanism. Do you agree or disagree with this student's claim?

2 N2O5 --> 4 NO2 + O2

• Agree

• Disagree

A hot piece of copper was dropped into 155mL of water at 23.6*C and 2.1 kJ of energy is transferred to the water. What is the final temperature of the water?

***Pay attention to sig figs!***

Tags

NGSS.HS-PS3-1

NGSS.HS-PS3-4

In the following equation, what does ΔT stand for?

q= m C Δ T

• mass

• specific heat

• change in temperature

• heat