What is the difference between chemical and physical properties? Physical properties are observed without changing the pure substance into a different substance. Chemical properties can be observed only by changing the pure substance into other substances

A metal melts at 450 o C. Physical or chemical property? Melting point is a physical property because the metal is still the same substance.

How are elements and compounds similar/different? Both are pure substances and have specific chemical and physical properties. Elements are the simplest substance while compounds are made of two or more elements

How does a heterogeneous mixture differ from a homogeneous mixture? Heterogeneous mixture – you can see the different parts. Homogeneous mixture – so thoroughly mixed that you cannot see the parts.

Why is it correct to say that seawater is a mixture? Seawater is a mixture of water, salt and other substances

What is mass? Mass is the amount of matter in an object Why is mass a more useful measure than weight for measuring matter? Mass is constant while weight changes based on gravitational pull.

What measurements must you make to find density? Mass and volume How can you determine whether a solid object is more dense or less dense than water? Put it in water. Float = less dense Sink = more dense

Identify three different kinds of physical change that could happen to a plastic spoon. Bend it. Break it. Melt it. Which of the following is not a physical change? a. Drying wet clothes b. Cutting snowflakes out of paper c. Lighting a match

What is thermal energy? The total energy of all the particles How can you tell whether one glass of water has more thermal energy than another, identical glass of water? Measure the temperature. Higher temperature = higher thermal energy

Which form of energy is represented by 1. a book lying on a desk 2. a book falling off a desk 1. potential energy 2. Kinetic energy

What happens to energy when matter undergoes a physical or chemical change? It transforms to another form of energy What forms of energy are given off When paper burns, and where does it come from? Electromagnetic and thermal energy that was stored as potential chemical energy in the paper.

Describe the energy changes that link sunshine to your ability to do pacers. Plants convert electromagnetic radiation to chemical energy during photosynthesis. When you eat the plants, your body converts the chemical energy to mechanical energy.