Balancing Equations
True or False: The number of atoms for each element must be equal on both sides of a balanced chemical equation.
a) True
b) False
c) Only for combustion reactions
a) True
Which type of reaction combines two or more substances to form one compound?
a) Decomposition
b) Combustion
c) Formation
c) Formation
What is a chemical reaction?
a) A change in state
b) A process where substances change into new substances with different properties
c) A change in texture
b) A process where substances change into new substances with different properties
What product is always formed in a combustion reaction?
a) Carbon monoxide
b) Water
c) Methane
b) Water
What is the symbol for gold on the periodic table?
a) Au
What is the correct coefficient for O₂ in the combustion reaction C₃H₈ + O₂ → CO₂ + H₂O?
a) 4
b) 5
c) 7
b)5
What type of reaction involves a single compound breaking into elements or simpler compounds?
a) Decomposition
b) Single replacement
c) Double replacement
a) Decomposition
Which of these is not evidence of a chemical reaction?
a) Formation of gas bubbles
b) Change in temperature
c) Dissolving sugar in water
c) Dissolving sugar in water
What is the product when hydrochloric acid reacts with sodium hydroxide?
a) Water and sodium chloride
b) Hydrogen gas and chlorine gas
c) Sodium hydroxide
a) Water and sodium chloride
What element is a diamond made of?
a) Carbon
b) Silicon
c) Nitrogen
a)carbon
What is the correct coefficient for Na in the equation Na + Cl₂ → NaCl?
a) 1
b) 2
c) 3
b) 2
In which reaction do ions "swap partners" to form new compounds?
a) Single replacement
b) Double replacement
c) Combustion
b) Double replacement
What is a reactant?
a) A substance formed in a chemical reaction
b) A substance consumed in a chemical reaction
c) A catalyst
b) A substance consumed in a chemical reaction
Predict the product: Mg + O₂ → ?
a) MgO
b) Mg₂O
c) MgO₂
a) MgO
What acid is found in your stomach?
a) Hydrochloric acid
b) Sulfuric acid
c) Nitric acid
a) Hydrochloric acid
Which of these equations is balanced?
a) 2H₂ + O₂ → H₂O
b) C₃H₈ + 4O₂ → 3CO₂ + 4H₂O
c) 2Na + Cl₂ → 2NaCl
c) 2Na + Cl₂ → 2NaCl
What type of reaction produces water and carbon dioxide from a hydrocarbon and oxygen?
a) Decomposition
b) Combustion
c) Formation
b) Combustion
Which law states that the mass of reactants equals the mass of products?
a) Law of Conservation of Mass
b) Law of Chemical Reactions
c) Law of Energy Conservation
a) Law of Conservation of Mass
What forms when calcium reacts with water?
a) Calcium oxide
b) Calcium hydroxide and hydrogen gas
c) Calcium chloride
b) Calcium hydroxide and hydrogen gas
Which gas is most abundant in Earth's atmosphere?
a) Oxygen
b) Nitrogen
c) Carbon dioxide
b) Nitrogen
What is the correct coefficient for H₂ in the equation H₂ + O₂ → H₂O?
a) 1
b) 2
c) 3
Correct Answer: b) 2
Identify this reaction: CuCl₂ + Zn → ZnCl₂ + Cu
a) Double replacement
b) Single replacement
c) Formation
b) Single replacement
What are the two types of energy changes in chemical reactions?
a) Thermal and kinetic
b) Exothermic and endothermic
c) Potential and mechanical
b) Exothermic and endothermic
Predict the precipitate when lead nitrate reacts with potassium iodide.
a) Potassium nitrate
b) Lead iodide
c) Lead nitrate
b) Lead iodide
What is the only metal that is liquid at room temperature?
a) Mercury
b) Gallium
c) Lead
a) Mercury