Endothermic And Exothermic
Q1. State what an exothermic reaction is.
A: An exothermic reaction is a reaction that releases heat energy to the surroundings.
State the gas that metals react with when they burn in air.
Response: Metals react with oxygen when they burn in air.
State the gas produced when metals react with water.
Response: Hydrogen gas is produced.
State the name of the tiny particle that makes up all matter.
An atom is the tiny particle that makes up all matter.
Identify the state of matter of ice.
Ice is a solid.
State what an endothermic reaction is.
An endothermic reaction is a reaction that absorbs heat energy from the surroundings.
State the general name of the compound formed when a metal reacts with oxygen.
A metal oxide is formed.
Identify the metal that reacts most gently with water.
Response:
Lithium reacts most gently.
Name the three sub-atomic particles found in an atom.
Protons, neutrons and electrons
Describe the shape and volume of a solid.
A solid has a fixed shape and fixed volume.
Q3. Identify the type of reaction when the surroundings become warmer.
A: Exothermic reaction.
Identify the metal that burns with a bright white flame.
Response: Magnesium burns with a bright white flame.
Describe what you observe when sodium reacts with water.
Describe what you observe when sodium reacts with water.
Response: Sodium floats, moves rapidly on the surface, fizzes, melts into a ball.
Describe where protons and neutrons are found in an atom.
Protons and neutrons are found in the nucleus at the centre of the atom.
Describe the shape and volume of a liquid.
liquid has a fixed volume but no fixed shape; it takes the shape of its container.
Q7. Give one example of an exothermic reaction.
A: Burning fuel (combustion).
. Name the compound formed when:
a) Sodium reacts with oxygen
Sodium oxide
Name the products formed when potassium reacts with water.
Potassium hydroxide and hydrogen gas are formed.
Explain why an atom has no overall charge.
An atom has no overall charge because it has equal numbers of protons and electrons, so the charges cancel out.
Why does the smell of perfume spread quickly in a room?
smell spreads because gas particles move freely and spread out quickly.
A student mixes two chemicals and the temperature falls from 25°C to 18°C. Identify the type of reaction and explain your answer.
It is an endothermic reaction because the temperature decreases, showing heat is absorbed.
Explain why potassium, sodium and lithium are stored under oil.
They are stored under oil to prevent them reacting with oxygen and moisture in the air.
Explain why magnesium is safer to use than potassium in classroom demonstrations with water.
Response:
Magnesium reacts much more slowly with water, making it less dangerous than potassium.
Draw and label a simple diagram of an atom showing the nucleus and electrons.
The diagram should show a central nucleus with protons and neutrons, and electrons in shells around it.
Name the change of state when a solid changes into a gas.
Sublimation