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
2. what is the formula mass of cacl₂? write your complete solution.
3. how many moles are present in 36 grams of h₂o? (molar mass of h₂o =
18 g/mol). write your complete solution.
4. find the molecular mass of glucose (c₆h₁₂o₆).
5. write the electron configuration of magnesium (atomic number 12).
6. balance the reaction: h₂+o₂→h₂o
7. give the correct name for fe₂o₃.

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
2.  what is the formula mass of cacl₂? write your complete solution.
3.  how many moles are present in 36 grams of h₂o? (molar mass of h₂o =
    18 g/mol). write your complete solution.
4.  find the molecular mass of glucose (c₆h₁₂o₆).
5.  write the electron configuration of magnesium (atomic number 12).
6.  balance the reaction: h₂+o₂→h₂o
7.  give the correct name for fe₂o₃.

Accepted Answer

### Question 2:
# Explanation:
## Step1: Recall formula mass definition
Formula mass is the sum of atomic masses of all atoms in a formula unit. For $\ce{CaCl2}$, we need atomic masses of Ca and Cl. Atomic mass of Ca is $40.08\ 	ext{g/mol}$, Cl is $35.45\ 	ext{g/mol}$.
## Step2: Calculate total mass for Cl
There are 2 Cl atoms, so mass of Cl is $2	imes35.45 = 70.90\ 	ext{g/mol}$.
## Step3: Add Ca and Cl masses
Formula mass of $\ce{CaCl2}$ is $40.08 + 70.90 = 110.98\ 	ext{g/mol}$.
# Answer:
The formula mass of $\ce{CaCl2}$ is $\boldsymbol{110.98\ 	ext{g/mol}}$ (or approximately $111\ 	ext{g/mol}$).

### Question 3:
# Explanation:
## Step1: Recall mole formula
Moles ($n$) = $\frac{	ext{mass}(m)}{	ext{molar mass}(M)}$. Given $m = 36\ 	ext{g}$, $M = 18\ 	ext{g/mol}$.
## Step2: Substitute values
$n=\frac{36\ 	ext{g}}{18\ 	ext{g/mol}}$.
## Step3: Calculate
$n = 2\ 	ext{moles}$.
# Answer:
There are $\boldsymbol{2}$ moles in 36 grams of $\ce{H2O}$.

### Question 4:
# Explanation:
## Step1: Recall atomic masses
C: $12.01\ 	ext{g/mol}$, H: $1.008\ 	ext{g/mol}$, O: $16.00\ 	ext{g/mol}$. For $\ce{C6H12O6}$, calculate mass of each element.
## Step2: Mass of C
$6	imes12.01 = 72.06\ 	ext{g/mol}$.
## Step3: Mass of H
$12	imes1.008 = 12.096\ 	ext{g/mol}$.
## Step4: Mass of O
$6	imes16.00 = 96.00\ 	ext{g/mol}$.
## Step5: Sum all masses
Molecular mass = $72.06 + 12.096 + 96.00 = 180.156\ 	ext{g/mol}$ (approx $180\ 	ext{g/mol}$).
# Answer:
The molecular mass of glucose ($\ce{C6H12O6}$) is $\boldsymbol{180.16\ 	ext{g/mol}}$ (or approximately $180\ 	ext{g/mol}$).

### Question 5:
# Explanation:
## Step1: Recall electron configuration rules
Magnesium (atomic number 12) has 12 electrons. Fill orbitals: 1s, 2s, 2p, 3s (following Aufbau principle).
## Step2: Fill 1s
$1s^2$ (2 electrons).
## Step3: Fill 2s
$2s^2$ (total 4 electrons).
## Step4: Fill 2p
$2p^6$ (total 10 electrons).
## Step5: Fill 3s
Remaining 2 electrons in $3s^2$. So electron configuration: $1s^2 2s^2 2p^6 3s^2$.
# Answer:
The electron configuration of Magnesium is $\boldsymbol{1s^2 2s^2 2p^6 3s^2}$ (or $[	ext{Ne}] 3s^2$).

### Question 6:
# Explanation:
## Step1: List atoms on each side
Left: H=2, O=2; Right: H=2, O=1.
## Step2: Balance O first
Multiply $\ce{H2O}$ by 2: $\ce{H2 + O2 -> 2H2O}$. Now O: 2 (left) vs 2 (right); H: 2 (left) vs 4 (right).
## Step3: Balance H
Multiply $\ce{H2}$ by 2: $\ce{2H2 + O2 -> 2H2O}$. Now H: 4 (left) vs 4 (right); O: 2 (left) vs 2 (right).
# Answer:
The balanced reaction is $\boldsymbol{2\ce{H2} + \ce{O2} -> 2\ce{H2O}}$.

### Question 7:
# Explanation:
## Step1: Identify ion charges
Fe in $\ce{Fe2O3}$: O is $-2$, so $2	imes	ext{Fe charge} + 3	imes(-2) = 0$ → Fe charge is $+3$ (ferric ion).
## Step2: Name using stock system
$\ce{Fe2O3}$ is Iron(III) Oxide (or Ferric Oxide).
# Answer:
The correct name for $\ce{Fe2O3}$ is $\boldsymbol{	ext{Iron(III) Oxide}}$ (or Ferric Oxide).

### Question 1:
#### Part (a) $\ce{NaCl}$:
# Brief Explanations:
$\ce{NaCl}$ is ionic. It forms between metal (Na, group 1) and nonmetal (Cl, group 17). Na donates an electron to Cl, forming $\ce{Na+}$ and $\ce{Cl-}$ ions, held by ionic bonds.
# Answer:
$\ce{NaCl}$: Ionic. Explanation: Formed by metal (Na) and nonmetal (Cl); involves electron transfer to form ions.

#### Part (b) $\ce{H2O}$:
# Brief Explanations:
$\ce{H2O}$ is polar covalent. O and H are nonmetals (covalent bond), but O is more electronegative, creating a dipole (partial + on H, partial - on O), so bond is polar, and molecule has net dipole.
# Answer:
$\ce{H2O}$: Polar Covalent. Explanation: Covalent bond with electronegativity difference (O > H) causing polar bonds and net molecular dipole.

#### Part (c) $\ce{Cl2}$:
# Brief Explanations:
$\ce{Cl2}$ is nonpolar covalent. Bond between two identical Cl atoms (same electronegativity), so electron pair is shared equally, no dipole.
# Answer:
$\ce{Cl2}$: Nonpolar Covalent. Explanation: Bond between identical atoms, equal electron sharing, no polarity.

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QUESTION IMAGE

Question

Explanation:

Question 2:

Step1: Recall formula mass definition

Step2: Calculate total mass for Cl

Step3: Add Ca and Cl masses

Step1: Recall mole formula

Step2: Substitute values

Step3: Calculate

Step1: Recall atomic masses

Step2: Mass of C

Step3: Mass of H

Step4: Mass of O

Step5: Sum all masses

Answer:

Question 3: