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4 years ago

The half-life for the radioactive decay of calcium-47 is 4.5 days. how many half-lives have elapsed after 27 days?

Chemistry

2 answers:

Evgesh-ka [11]4 years ago

8 0

1 half-life - 4.5 days
x half-lives - 27 days

x=(1*27)/4.5=6
6 half-lives have elapsed after 27 days.

Pani-rosa [81]4 years ago

6 0

Answer: The number of half lives are 6

Explanation:

We are given:

Half life of a radioactive isotope = 4.5 days

Calculating the number of half lives after time has elapsed 27 days:

4.5 days have been elapsed time after 1 half life

So, 27 days must have been elapsed after = $\frac{1}{4.5}\times 27=6$ half lives

Hence, the number of half lives are 6

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3 years ago

What is the limiting reactant in a reaction where 10.0 mol of iron is treated with 12.0 mol of bromine? The product that forms i

hammer [34]

Answer: The limiting reagent in the reaction is bromine.

Explanation:

Limiting reagent is defined as the reagent which is completely consumed in the reaction and limits the formation of the product.

Excess reagent is defined as the reagent which is left behind after the completion of the reaction.

Given values:

Moles of iron = 10.0 moles

Moles of bromine = 12.0 moles

The chemical equation for the reaction of iron and bromine follows:

$2Fe+3Br_2\rightarrow 2FeBr_3$

By the stoichiometry of the reaction:

If 3 moles of bromine reacts with 2 moles of iron

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Hence, bromine is considered a limiting reagent because it limits the formation of the product.

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3 years ago

Silicon carbide (SiC) is an important ceramic material made by reacting sand (silicon dioxide, SiO2) with powdered carbon at a h

makkiz [27]

Answer:

Percent yield of SiC is 77.0%.

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Therefore, 1664 moles of $SiO_{2}$ produce 1664 moles of SiC

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