The initial concentration of a in the first-order reaction 4a→4b+c is 0.933 mol l−1. given that the rate constant is 0.310 s−1, what is the half-life of the reaction in seconds? remember to use correct significant figures in your answer (round your answer to the nearest hundredth). do not include units in your response.

The half-life of the reaction in 2.24 seconds.

Explanation:

We are given a reaction which follows first order kinetics.

The formula used to calculate the half -life of the reaction for first order kinetics follows:

where,

= half-life of the reaction

k = rate constant of the reaction =

Putting values in above equation, we get:

The rule which is applied for multiplication and division problems is that the least number of significant figures in any number of a problem will determine the number of significant figures in the solution.

In the problem, the least precise significant figures are 3. Thus, the answer will also have 3 significant figures.

Hence, the half-life of the reaction in 2.24 seconds.

given:

mass of na = 115 g

excess cl2

to determine:

mass of nacl produced

explanation:

given reaction is-

2na(s) + cl2(g) → 2nacl(s)

since cl2 is in excess, na will be the limiting reagent

as per the reaction stoichiometry na: nacl = 1: 1

i.e. moles of na reacted = moles of nacl formed

now, # moles of na = mass of na/atomic mass

                                  = 115 g/23 g.mol-1 = 5 moles

therefore, moles of nacl = 5

molar mass of nacl = 58 g/mol

mass of nacl = 5 moles * 58 g.mol-1 = 290 g

ans: amount of nacl produced = 290 g

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