States of Matter
What is the state of matter where particles are tightly packed and only vibrate in place?
A solid.
What is the simplest type of substance, made up of only one type of atom?
An element.
What is the term for a change where new substances are formed?
A chemical Change
What is a physical change?
A change in the appearance or state of a substance without forming a new substance.
Who is credited with creating the first widely accepted periodic table?
Dmitri Mendeleev.
In which state of matter do particles move freely and fill the entire space of their container?
A gas.
What do you call a substance made of two or more elements chemically bonded together?
A compound.
Name two signs that a chemical change has occurred.
Colour change, gas production, temperature change, or formation of a precipitate
Is melting ice a physical or chemical change? Why?
A physical change, because the water changes state from solid to liquid but remains the same substance.
What was unique about Mendeleev’s periodic table compared to earlier attempts?
He left gaps for undiscovered elements and predicted their properties.
Explain why liquids can flow but solids cannot.
Because liquid particles are close together but can slide past each other, while solid particles are fixed in place.
How is a mixture different from a compound?
A mixture is made of substances that are not chemically bonded and can be separated physically whereas in a compound the substances are chemically bonded.
What happens to the atoms in a chemical reaction?
The atoms rearrange to form new substances.
Name two examples of physical changes other than melting.
Boiling water, freezing water, dissolving sugar in water, or breaking a piece of glass.
How are elements arranged in the modern periodic table?
By increasing atomic number.
What happens to the motion of particles when a solid is heated and melts into a liquid?
The particles gain energy, vibrate faster, and eventually break free from their fixed positions.
Describe the particle arrangement in a homogeneous mixture.
The particles are evenly distributed throughout the mixture.
Why is burning wood considered a chemical change?
Because it produces new substances like ash, carbon dioxide, and water vapour.
How can you tell the difference between a physical change and a chemical change?
A physical change does not create a new substance, while a chemical change results in new substances being formed.
How did the discovery of protons and neutrons influence the modern periodic table?
It allowed elements to be arranged by atomic number rather than atomic mass, resolving inconsistencies in Mendeleev’s table.
Why does a gas compress more easily than a liquid or solid?
Because gas particles are far apart, leaving more space to compress.
Give an example of a compound and explain why it is not a mixture.
For example: Water (H₂O), because its hydrogen and oxygen atoms are chemically bonded together.
Explain why the mass of substances is conserved during a chemical reaction
Because atoms are not created or destroyed, only rearranged (law of conservation of mass)?
Explain why dissolving salt in water is considered a physical change, even though the salt seems to disappear.
Because the salt particles are still present in the water and can be recovered by evaporating the water.