Answer:
The answer is D. It changes the final products of the reaction. .
Explanation:
- <u>. Catalyst is a substance that increases the rate of a reaction without itself being consumed.</u>
Given :
Initial mass , a = 150 gm .
Half time ,
.
Final mass , x = 18.75 gm .
To Find :
The time taken to decay 18.75 gm .
Solution :
We know , time taken is given by :

Here , k is a constant given by :

Putting all given value in above equation :
We get :

Therefore , time taken is 6.94 hours .
Hence , this is the required solution .
Answer:
2.53 grams of hydrogen gas will be produced and 12.2 many grams of the excess reactant i.e. calcium will be left over.
Explanation:

Moles of calcium = 
Moles of HCl = 
According to reaction, 2 moles of HCl reacts with 1 mole of calcium :
Then 2.53 moles of HCl will recat with :
of calcium.
As we can see moles of calcium are in excessive amount. Hence calcium is an excessive reagent.
Moles of calcium left unreacted =1.57 mol - 1.265 mol =0.305 mol
Mass calcium left unreacted = 0.305 mol × 40 g/mol =12.2 g
Since, calcium is an excessive reagent HCl is limiting reagent and the amount of hydrogen gas produced will depend on HCl .
According to reaction, 2 moles of HCl gives 1 mole of hydrogen gas.
Then 2.53 moles of HCl will give:
of hydrogen gas.
Mass of 1.265 mol of hydrogen gas = 1.265 mol × 2 g/mol = 2.53 g
2.53 grams of hydrogen gas will be produced and 12.2 many grams of the excess reactant i.e. calcium will be left over.
Answer:
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Explanation:
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