Worksheetsenergy changes (marked work)
Total questions: 10
Worksheet time: 10mins
When a cracker is ignited, a sudden reaction takes place with the release of heat, light and sound. Identify the process:
Rusting
Combustion
Reduction
Endothermic
Hydrocarbon fuel + oxygen ----> ___+ water
Carbon dioxide
Hydrogen
Oxygen
Metal oxide
In which tube will the nail go rusty?
The nail in tube A will go rusty.
The nail in tube B will go rusty.
The nail in tube C will go rusty
A gas was tested by bringing a glowing/burning splint close to it. A pop sound was heard afterwards. What gas was tested?
Oxygen
Carbon dioxide
Nitrogen
Hydrogen
Which acid is used in the following chemical reaction:
Calcium + acid ---> calcium sulfate + hydrogen
Hydrochloric acid
Nitric acid
Sulfuric acid
Citric acid
If potassium reacts with water what are the 2 products of the reaction?
potassium hydroxide + oxygen
potassium hydroxide + hydrogen
potassium + hydrogen oxide
potassium hydroxide + hydrogen oxide
A student mixed two chemicals to allow them to react. The temperature before the reaction was 25 ° C. The temperature after the reaction was 18° C. Which of the following is true?
It is an endothermic reaction
It is an exothermic reaction
When a candle is lit, hydrocarbons are combusting. An exothermic reaction is occurring. Energy is being _________________ .
Absorbed
Frozen
Destroyed
Released
Examine the following reaction. Is it endothermic or exothermic and how do you know?
MgO + CaS ----> CaO + MgS + 200 kJ
Exothermic; energy is written on the product side
Endothermic; energy is written on the reactant side.
Exothermic; energy is written on the reactant side
Endothermic; energy is written on the product side
Self heating cans are usually expensive as the compartments in the tin are:
Made up of expensive materials
Take longer time to heat up.
Difficult to make to prevent contamination of food or drinks.
Only manufactured in few countries
