Question

chapter 5 assignment molecules and compounds mariana salano 9172125 true/false. write t if the statement is true and f if the statement is false. 1) the properties of a compound are an average of the properties of the individual elements. 2) although some substances we encounter in our routine lives are elements, most occur in the combined state. 3) the fact that water has an oxygen - to - hydrogen mass ratio of 8.0 illustrates the law of conservation of mass. 4) the subscripts in a chemical formula do not change for a given compound. 5) carbon dioxide is an example of a molecular compound. 6) ionic compounds always contain positive and negative ions. 7) the ionic compound mgo is named manganese oxide. 8) the correct formula for calcium fluoride is caf3. 9) the proper name for sf6 is sulfur tetrafluoride. 10) the correct name for hno3 is hydronitric acid. multiple choice. choose the one alternative that best completes the statement or answers the question. 11) the oxygen - to - hydrogen mass ratio of water is always 8.0 is an example of what fundamental law? a) law of conservation of mass b) law of constant whole number ratio c) law of constant mass ratio d) law of constant composition e) none of the above 12) what is the oxygen - to - sulfur mass ratio of sulfur dioxide? a) 0.5 b) 1.0 c) 2.0 d) 16 e) none of the above

Explanation:

Step1: Analyze statement 1

A compound has unique properties different from its constituent elements, not an average. So it's false.

Step2: Analyze statement 2

Most substances in daily - life are compounds (combined state), with only a few elements. So it's true.

Step3: Analyze statement 3

The oxygen - to - hydrogen mass ratio of water illustrates the law of constant composition, not the law of conservation of mass. So it's false.

Step4: Analyze statement 4

The subscripts in a chemical formula represent the fixed ratio of atoms in a compound and do not change for a given compound. So it's true.

Step5: Analyze statement 5

Carbon dioxide ($CO_2$) is made up of molecules, so it is a molecular compound. So it's true.

Step6: Analyze statement 6

Ionic compounds are composed of positive and negative ions. So it's true.

Step7: Analyze statement 7

$MgO$ is magnesium oxide, not manganese oxide. So it's false.

Step8: Analyze statement 8

The correct formula for calcium fluoride is $CaF_2$, not $CaF_3$. So it's false.

Step9: Analyze statement 9

The proper name for $SF_6$ is sulfur hexafluoride, not sulfur tetrafluoride. So it's false.

Step10: Analyze statement 10

The correct name for $HNO_3$ is nitric acid, not hydronitric acid. So it's false.

Step11: Analyze question 11

The oxygen - to - hydrogen mass ratio of water being always 8.0 is an example of the law of constant composition.

Step12: Analyze question 12

The formula of sulfur dioxide is $SO_2$. The molar mass of oxygen is approximately 16 g/mol and of sulfur is approximately 32 g/mol. In $SO_2$, there are 2 oxygen atoms and 1 sulfur atom. The oxygen - to - sulfur mass ratio is $\frac{2\times16}{32}=1.0$.

Answer:

1. F
2. T
3. F
4. T
5. T
6. T
7. F
8. F
9. F
10. F
11. D. Law of Constant Composition
12. B. 1.0