Page 61 - 新思维科学学生用书7 样章

2 Materials and their structure

Questions

10 Which of these substances are elements, and which are compounds? Explain your answer.

K O NaCl Al Ca CaCl H
2 2 2
11 The formula for sulfur dioxide is SO .
2
a How many different elements are combined in sulfur dioxide?
b How many atoms of oxygen are combined with each atom of sulfur?

12 The formula for water is H O.
2
a Which two elements are combined in water?
b What does the formula tell you about the numbers of each kind of atom that are combined

together?
13 The compound with the formula CO is called carbon monoxide. Suggest why it is not simply
called ‘carbon oxide’.
14 Suggest the names of the compounds with these formulae:
a MgO

b NaCl
c CaCl .
2
15 The formula for sodium hydroxide is NaOH; the formula for potassium hydroxide is KOH.

Which two elements do you think are contained in all hydroxides?
16 What is the name of the compound with the formula LiOH?
17 How many different elements are combined together in LiOH?

60