WorksheetsChemical Reactions and Energy
Total questions: 27
Worksheet time: 41mins
Energy is _____ when new bonds form.
absorbed
released
lost
gained
Energy is ______ when bonds break.
gained
lost
released
absorbed
The energy required to start a chemical reaction is ___.
endothermic
exothermic
activation
released
An _______ reaction is when more energy is released than is absorbed. This energy can be in the form of light, heat, electricity, etc.
endothermic
endergonic
exothermic
exergonic
Which of the following categories of reactions can be used to classify both physical and chemical changes? (Multiple Response-MR)
endergonic
endothermic
exergonic
exothermic
An _______ reaction is when more energy is absorbed than is released. This energy can be in the form of light, heat, electricity, etc.
endothermic
endergonic
exothermic
exergonic
An _______ reaction is when more thermal energy is absorbed than is released.
endothermic
endergonic
exothermic
exergonic
An _______ reaction is when more thermal energy is released than is absorbed.
endothermic
endergonic
exothermic
exergonic
CaCO3 represents a chemical
formula
subscript
symbol
reaction
The minimum amount of energy needed to start a reaction is the.......
activation energy
exothermic energy
chemical energy
endothermic energy
What happens when chemical bonds break and new bonds form?
a chemical change.
mattered is destroyed.
surface area increases.
a physical change
In chemical reactions, what does the law of conservation of mass mean/
Matter is not created or destroyed.
The total mass of the reactants is greater than the total mass of the products.
The total mass of the reactants is less than the total mass of the poducts.
Matter is not changed.
Na+Cl2 → 2NaCl
A chemical change is different than a physical change because in a chemical change
chemicals are used
molecules do not physically touch
a new substance is formed and in a physical no new substance is formed
the change can be seen but in a physical change it cannot
Which of the following 2 are chemical reactions?
sugar dissolving in water
water turning into steam
burning wood
mixing baking soda and vinegar
tearing paper
Some chemical reactions require a substance called a catalyst. The purpose of a catalyst is
to warm up the reaction
to speed up the reaction
to create more reactants
to stop the reaction
What is the purpose of photosynthesis. Select all that apply.
to form glucose, food for the plant
to form carbon dioxide
to form oxygen
to form energy
to form water
Maria’s father started a fire in the fireplace. He crumpled some paper, lit a match, and soon the logs in the fireplace were burning. In this case, the stored chemical energy in the logs was changed into
electrical energy.
mechanical motion.
heat and light energy.
electrical and heat energy.
