SRA #7

The chemical formula for rust is Fe2O3. Which chemical formula has the same number of oxygen atoms as rust?

• CaCO3
• H2O
• NO2
• HClO4

Is the chemical equation properly balanced?

• No. There are two chlorine atoms on the reactant side and only one chlorine atom on the product side
• No. There are two chlorine atoms on the product side and only one chlorine atom on the reactant side
• Yes. There is one of each atom on the right side of the equation.
• Yes. The number and type of atoms on each side of the equation are the same.

Which table represents the numbers of carbon, oxygen, and hydrogen atoms that are present on both sides of the balanced chemical reaction?

• A
• B
• C
• D

If 25 grams of CuO react with 2 grams of C, and both compounds react completely, what is the combined mass of CO2 and Cu that is formed?

• 23 grams
• 25 grams
• 27 grams
• 29 grams

Which element in the reaction is unbalanced?

• carbon
• hydrogen
• oxygen
• sunlight

How many atoms will be in the total amount of product?

• 100 atoms
• 150 atoms
• 200 atoms
• 250 atoms

How many carbon (C) atoms will be present on the products side to follow the Law of Conservation of Mass?

• 2
• 4
• 6
• 12

Is the chemical equation balanced, and why?

• No.

• Yes.

The chemical formula for calcium phosphate is Ca3(PO4)2. How many phosphorus atoms are represented in this formula?

• 1
• 2
• 4
• 8

The student concludes that gases weigh less than solids and liquids. What is an acceptable alternative conclusion?

• The baking soda partially dissolves in the acetic acid, causing it to weigh less.
• The mass of the acetic acid solution is converted into heat, which weighs less.
• The container that had the acetic acid solution is empty, which leads to a decrease in the total mass
• The gas formed after mixing the acetic acid and the baking soda moves out of the container, which leads to a decrease in the total mass