Question

Charlie is balancing an equation. She has identified the atoms and counted the number of each in the reactants and products. What would Charlie adjust to make the number of atoms in the reactants the same as the number of atoms in the products?

coefficients
subscripts
superscripts
parentheses



Lana balanced an equation so that the result was 2C2H3Br + 5O2 → 4CO2 + 2H2O + 2HBr. Which most likely represents the starting equation?

2C4H3Br + 5O2 → 4CO2 + 2H2O + 2HBr
C2H3Br + 5O2 → 4CO2 + H2O + 2HBr
C4H3Br + O2 → CO2 + H2O + HBr
C2H3Br + O2 → CO2 + H2O + HBr



Plants use sunlight as energy to convert carbon dioxide and water into glucose and oxygen. Which best describes the reaction?

The law of conservation of mass indicates the same amount of carbon will be found in the reactants as in the products.
The law of conservation of energy indicates the same amount of carbon will be found in the reactants as in the products.
The law of conservation of mass indicates the same amount of glucose will be found in the reactants as in the products.
The law of conservation of energy indicates the same amount of glucose will be found in the reactants as in the products.


The equation below is for potassium oxide.
4K + O2 2K2O
What is the ratio of atoms of potassium to atoms of oxygen?

1:2
2:1
4:1
1:4



The amount of oxygen in the reactants is 4 atoms. In the products, the oxygen is distributed to water (H2O) and O2 gas. Which coefficients would be placed in front of water and oxygen?

2 in front of water and 2 in front of oxygen
1 in front of water and 2 in front of oxygen
1 in front of water and 1 in front of oxygen
2 in front of water and 1 in front of oxygen

Answer 1

1) coefficients

2) C2H3Br + O2 → CO2 + H2O + HBr

3) The law of conservation of mass indicates the same amount of carbon will be found in the reactants as in the products.

4) 2:1

5) 2 in front of water and 1 in front of oxygen