Question

calculate the mass of potassium chlorate required to produce 35 g of potassium chloride on complete decomposition

Answer 1

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Answer: 57.55 g

Explanation

1. Write the balanced equation

$\mathbb{2KCLO_3 \rightarrow 2KCL + O_2}$

2. Calculate the atomic mass

$\rm {2[ 39 + 35.5 + (16 \times 2) \rightarrow 2(39 + 35.5) + 3(32)} \\ \rm2(39 + 35.5 + 48) \rightarrow 2 \times 74.5 + 96 \\ \rm 2 \: \times \: 122.5 \rightarrow 149 + 96 \\ \rm245 \rightarrow 245$

3. From the equation we can find that to produce 149 g of KCL we need 245 g of $\mathbb{KCLO_3}$.

Hence, 149 g of $\mathbb{KCL}$ is produced by $\large\bf{245}$ g of $\mathbb{KCLO_3}$.

1 g of $\mathbb{KCL}$ is produced by $\large \bf \frac{245}{149}$ g of $\mathbb{KCLO_3}$.

35 g of $\mathbb{KCL}$ is produced by $\large \bf \frac{245}{149} \times 35 = 57.55$ g of $\mathbb{KCLO_3}$.

Answer 2

Reaction :

$2 KClO_3\rightarrow 2KCl +O_2$

Gram mass of 2 KClO₃

K = 39

Cl = 35.5

O = 16

2 ( 39 + 35.5 + 48 )

= > 2 × 122.5

= > 245

This means that 245 g of potassium chlorate was used .

Now mass of potassium chloride is 2 ( 39 + 35.5 )

= > 2 × 74.5

= > 149 g

Hence 149 g of KCl is produced per 245 g .

1 g is produced per 245 / 148 g

35 g is produced per 245 / 148 g × 35

= > 57.939 g

= > 57.94 g

The mass will be 57.94 g