HSC Science (Computer Science) 12th Standard Board Exam - Maharashtra State Board Important Questions for Chemistry

The half life period of a first order reaction is 6. 0 h . Calculate the rate constant

What is the role of the following compound- 
SiO₂ in the extraction of copper from copper pyrites?

In a first-order reaction A → product, 80% of the given sample of compound decomposes in 40 min. What is the half-life period of the reaction? 

Answer the following in one or two sentences.

Why all collisions between reactant molecules do not lead to a chemical reaction?

Answer the following in brief.

How instantaneous rate of reaction is determined?

Answer the following in brief.

Obtain the relationship between the rate constant and half-life of a first-order reaction.

What are pseudo-first-order reactions?

Answer the following in brief.

Explain graphically the effect of temperature on the rate of reaction.

Solve

The half-life of a first-order reaction is 1.7 hours. How long will it take for 20% of the reactant to react?

Show that the time required for 99.9% completion of a first-order reaction is three times the time required for 90% completion.

How will you determine activation energy from rate constants at two different temperatures?

Answer the following in brief.

Give one example and explain why it is pseudo-first-order.

The rate law relates to the rate of a chemical reaction in terms of _______.

For first order reaction, the rate constant for the decomposition of N₂O₅ is 6 × 10^–4 s ^–1. The half-life period for decomposition in seconds is ______.

Effect of catalyst in a chemical reaction is to change the _______.

Give one example of a pseudo first-order reaction.

Explain pseudo first order reaction with a suitable example.

Explain with the help of a potential energy diagram that the catalyst increases the rate of the reaction.

For the reaction 2A + B → C, rate of disappearance of A 0.076 mol s ^–1.

1. What is the rate of formation of C?
2. What is the rate of consumption of B?
3. What is the rate of the overall reaction?

In a first-order reaction A → B, 60% of a given sample of a compound decomposes in 45 mins. What is the half-life of reaction? Also, write the rate law equation for the above first-order reaction.