Question

lecture activity no. 1

since we only have a 1-hour class schedule, this will serve as your activity to
review some of the difficult concepts in inorganic chemistry (based on your
answers). be prepared for the recitation.

1. classify the following compounds as ionic, polar covalent, or nonpolar

covalent. explain your answer. a) nacl; b) h₂o; c) cl₂

1. what is the formula mass of cacl₂? write your complete solution.
2. how many moles are present in 36 grams of h₂o? (molar mass of h₂o =

18 g/mol). write your complete solution.

1. find the molecular mass of glucose (c₆h₁₂o₆).
2. write the electron configuration of magnesium (atomic number 12).
3. balance the reaction: h₂+o₂→h₂o
4. give the correct name for fe₂o₃.

Explanation:

Question 2:

Step1: Identify atomic masses

Atomic mass of Ca: $40.08\ \text{g/mol}$, Cl: $35.45\ \text{g/mol}$.

Step2: Calculate formula mass

Formula mass of $\ce{CaCl2}$ = mass of Ca + 2×mass of Cl.
$= 40.08 + 2\times35.45$
$= 40.08 + 70.90$
$= 110.98\ \text{g/mol}$

Step1: Recall mole formula

Moles ($n$) = $\frac{\text{mass}(m)}{\text{molar mass}(M)}$.

Step2: Substitute values

Given $m = 36\ \text{g}$, $M = 18\ \text{g/mol}$.
$n = \frac{36}{18} = 2\ \text{moles}$.

Step1: Atomic masses

C: $12.01\ \text{g/mol}$, H: $1.008\ \text{g/mol}$, O: $16.00\ \text{g/mol}$.

Step2: Calculate molecular mass

Molecular mass of $\ce{C6H12O6}$ = $6\times12.01 + 12\times1.008 + 6\times16.00$
$= 72.06 + 12.096 + 96.00$
$= 180.156\ \text{g/mol}$ (≈180.16 g/mol)

Answer:

The formula mass of $\ce{CaCl2}$ is $\boldsymbol{110.98\ \text{g/mol}}$.

Question 3: