Chemistry

What is a chemical reaction? Provide an example of a chemical reaction.

A chemical reaction is when a starting substance is changed and made into new, ending substances. The atoms rearrange. ex ; when tums turns your stomach acid into a new substance

What is the difference between an element and a compound? Give two examples of elements and two examples of compounds.

An element is just one element, and a compound is made of more than 2 elements combined. elements ; ( O ) , ( H ) compounds ; ( H2O ) , ( CO2 )

What happens to a volume of air when it is heated? Does it compress, contract, or expand?

It expands because more heat = more kinetic energy. The more kinetic energy there is, the more the particles will bounce off each other harder and it will push the particles apart which causes it to take up more space.

As a result of a chemical reaction, what are formed?

New substances

When a volume of air is heated in a closed balloon, four things happen

Particles bounce off each other more often, particles move faster, takes up more space, and spreads more apart

Which of the following are NOT chemical reactions? & Why ? - a match burning - sugar dissolving in water - a firework exploding - a nail rusting - melting wax - boiling water - digesting food in your stomach

Sugar dissolving in water, water boiling, and melting wax. Because they did not create any new substances.

Sugar can melt and sugar can dissolve. What is the difference between melting and dissolving? Discuss what happens to the particles in both situations.

The difference between melting and dissolving is that when the sugar melts, the particles in the sugar increases in kinetic energy and the particles slide past each other. And in dissolving, the sugar particles break apart and spreads evenly through out the water particles. The sugar melts because of heat, and the sugar dissolves because of a liquid