Conservation of Mass Quiz

An equation for a chemical reaction is shown.

NaOH + HCl $$\rightarrow$$ NaCl + H₂O

Which statement provides the best evidence that mass is conserved in the reaction?

A chemical equation for the reaction between calcium hydroxide, Ca(OH)₂, and sulfuric acid, H₂SO₄, is shown. The masses of some of the reactants and products are given in grams.

Ca(OH)₂ + H₂SO₄ $$\rightarrow$$ CaSO₄ + 2H₂O

Ca(OH)₂: 74 g

CaSO₄: 136 g

2H₂O: 36 g

How many grams of sulfuric acid were used in the reaction?

Two solutions are mixed and react to form the solidprecipitate AgCl. The chemical reaction is shown by the balanced equation.

AgNO₃ + NaCl $$\rightarrow$$ AgCl + NaNO₃

What happens to the total mass as the reaction takes place?

As part of an investigation, students combined substances in a beaker to observe chemical reactions. They performed two procedures. They measured the mass of each substance before and after each reaction. The table shows their observations.

Assuming the students did not make any careless errors, what likely explains these changes in mass?

A chemical reaction in which calcium carbonate, CaCO₃, is decomposed results in the production of two simpler compounds.

CaCO₃ $$\rightarrow$$ CaO + CO₂

There are 28.00g of CaO and 21.97 g of CO₂.

What mass of calcium carbonate, to the nearest hundredth of a gram, is decomposed in this reaction?

Record your answer as a number. Be sure to use the correct place value.

The following is the chemical equation for photosynthesis.

H₂O + CO₂ $$\rightarrow$$ O₂ + C₆H₁₂O₆

Is this chemical equation balanced? Explain your reasoning.