Question

compound a has a mass of 7g and compound b has a mass of 5g. when they react, no gas is released. what is the mass of the newly - formed substance?
a 2g
b 15g
c 12g
d 25g

Explanation:

Step1: Apply law of conservation of mass

According to the law of conservation of mass, in a chemical reaction where no gas is released, the total mass of reactants equals the mass of the product.
The mass of Compound A is 7g and the mass of Compound B is 5g.
The total mass of reactants is $7 + 5$.

Step2: Calculate the mass of the newly - formed substance

$7+5 = 12$g

Answer:

C. 12 g