Answer:
I'd Go. B. weigh everything, let the reaction happen, then weigh everything again.
Answer:
The law is observed in the given equation.
Explanation:
CaCO₃ + 2HCI → CaCI₂ +H₂O + CO₂
In order to find out if the law of conservative mass is followed, we need to <u>count how many atoms of each element are there in both sides of the equation</u>:
- Ca ⇒ 1 on the left, 1 on the right.
- C ⇒ 1 on the left, 1 on the right.
- O ⇒ 3 on the left, 3 on the right.
- H ⇒ 2 on the left, 2 on the right.
- Cl ⇒ 2 on the left, 2 on the right.
As the numbers for all elements involved are the same, the law is observed in the given equation.
Answer:
The expression to calculate the mass of the reactant is 
Explanation:
<em>The amount of heat released is equal to the amount of heat released per gram of reactant times the mass of the reactant.</em> To keep to coherence between units we need to transform 1,080 J to kJ. We do so with proportions:

Then,

Hello there! With the values of density and volume, you would be able to find the object's mass.
Density is found by dividing the mass by the volume, so you could place in the values of the density and the volume to get the mass.
For example:
500 = mass/10
The 500 being density and 100 being volume. You would use simple math rules and multiply 10 by 500, and you'd get 5000, therefore using the density and volume values and giving you the mass.
I hope I could help you and have a great day!