Science 10
Unit 1: Chemical Reactions
What You Should Know!
Check What You Recall
1. Window glass has a smooth texture. Brick has a rough texture. Are these examples of a physical
property or a chemical property? Explain your answer.
2. Identify the types of properties described in this sentence, and give reasons for your choice:
“Beeswax is soft and burns with a bright flame.”
3. Decide whether each statement below describes a physical property or a chemical property of a
substance. Then indicate whether it is a qualitative property or a quantitative property.
(a) It is a pale yellow gas at room
temperature.
(c) Its density is 1.695 g/L.
(d) It explodes when it reacts with water.
(b) It can burn or etch glass permanently.
(e) Its melting point is 0°C.
4. Which chemical property of propane would be most important to keep in mind when using a gas
barbecue? Explain your answer.
5. Tetrafluoromethane is a compound that is a potent greenhouse gas. It lasts for a long time in the
atmosphere because it does not readily break down or react with other substances. What chemical
properties of tetrafluoromethane are described here?
Check What You Recall
6. Classify the following materials as mixtures or pure substances.
(a) soup
(d) carbon dioxide
(b) bronze
(e) air
(c) oxygen
(f) gasoline
7. Classify the following pure substances as elements or compounds.
(a) carbon
(b) water
(c) silicon dioxide
(d) nitrogen
8. Saltwater is a solution that contains two pure substances that happen to be compounds: water
and salt.
(a) Suggest a way you could get the salt from the water.
(b) Is there a physical method by which you could break down the salt or water further? Explain
your answer.
Check What You Recall
9. Indicate whether the following statements are true or false. If the statement is false, rewrite it to
make it true.
(a) In science, laws do not explain anything; they just describe and summarize what happens.
(b) A scientific theory rarely involves an explanation of why something happens.
(c) Only a few investigations are conducted before a theory is accepted by scientists.
Check What You Recall
11. Copy and complete the following table.
12. The atomic number for nitrogen is 7. How many protons and electrons does an atom of
nitrogen have?
13. What is the chemical symbol for these elements?
(a) gold
(d) argon
(b) aluminum (e) silver
(c) antimony
14. What are the chemical symbols for the following elements: helium, aluminum, tungsten,
cadmium, krypton, francium, cobalt, and barium? (Refer to a periodic table.)
15. Which element is found in Group 3 and Period 5 of the periodic table?
16. Only two elements are liquids at room temperature. Which two are they? (Refer to a periodic
table.)
17. Which of the following is not a classification of elements represented on the periodic table?
(a) solids, liquids, and gases
(c) earth, water, and air
(b) metals, non-metals, and metalloids
(d) natural elements and synthetic elements
18. List three elements found in Period 2 of the periodic table.
19. List two elements found in Group 2 of the periodic table.
20. The noble gases are the elements in Group 18 of the periodic table. These non-metals are all
odourless, colourless gases at room temperature. Look at the periodic table and then list the noble
gases, including the chemical symbol for each gas.
21. Using your periodic table, identify the information listed below for the element beryllium.
(c) number of protons
(a) symbol
(d) number of electrons
(b) name of group
(e) atomic number