Question

1. what is the name of hi?

a) hydroiodous acid
b) hydroiodic acid
c) iodous acid
d) iodic acid
e) none of the above

1. what is the name of hno₂?

a) hydronitric acid
b) nitric acid
c) hydronitrous acid
d) nitrous acid
e) none of the above

1. what is the formula mass for potassium nitrate?

a) 101.10 amu
b) 92.99 amu
c) 117.11 amu
d) 85.11 amu
e) none of the above

1. which of the following has the largest formula mass?

a) co₂
b) sio₂
c) h₂o
d) no₂
e) so₂

Explanation:

Step1: Recall naming of binary acids

Binary acids with hydrogen and a non - oxygen element are named as hydro - <non - oxygen element root> - ic acid. For HI, the non - oxygen element is iodine. So, it is hydroiodic acid.

Step2: Recall naming of oxyacids

For $HNO_2$, the polyatomic ion is nitrite ($NO_2^-$). Oxyacids with the polyatomic ion ending in - ite are named as <root of polyatomic ion> - ous acid. So, $HNO_2$ is nitrous acid.

Step3: Calculate formula mass of potassium nitrate

The formula of potassium nitrate is $KNO_3$. The atomic masses are: $K = 39.10$ amu, $N=14.01$ amu, $O = 16.00$ amu. The formula mass $=39.10+14.01 + 3\times16.00=39.10 + 14.01+48.00 = 101.11$ amu (close to 101.10 amu considering rounding differences).

Step4: Calculate formula masses of given compounds

For $CO_2$: Atomic masses: $C = 12.01$ amu, $O = 16.00$ amu. Formula mass $=12.01+2\times16.00=44.01$ amu.
For $SiO_2$: Atomic masses: $Si = 28.09$ amu, $O = 16.00$ amu. Formula mass $=28.09+2\times16.00 = 60.09$ amu.
For $H_2O$: Atomic masses: $H = 1.01$ amu, $O = 16.00$ amu. Formula mass $=2\times1.01+16.00 = 18.02$ amu.
For $NO_2$: Atomic masses: $N = 14.01$ amu, $O = 16.00$ amu. Formula mass $=14.01+2\times16.00 = 46.01$ amu.
For $SO_2$: Atomic masses: $S = 32.07$ amu, $O = 16.00$ amu. Formula mass $=32.07+2\times16.00 = 64.07$ amu. So, $SO_2$ has the largest formula mass.

Answer:

1. C. hydroiodic acid
2. D. Nitrous acid
3. A. 101.10 amu
4. E. $SO_2$