Question

one reaction that produces hydrogen gas can be represented by the unbalanced chemical equation Mg(s)+HCI(aq) -> MgCI(aq)+H2(g). What is the mass of HCI is consumed by the reaction of 3.25 mol of magnesium?

Answer 1

Answer:

128 g HCl

General Formulas and Concepts:

Math

Pre-Algebra

Order of Operations: BPEMDAS

1. Brackets
2. Parenthesis
3. Exponents
4. Multiplication
5. Division
6. Addition
7. Subtraction

• Left to Right

Chemistry

Atomic Structure

• Reading a Periodic Table

Stoichiometry

• Reaction Mole Ratios
• Using Dimensional Analysis

Explanation:

Step 1: Define

[RxN - Unbalanced] Mg (s) + HCl (aq) → MgCl (aq) + H₂ (g)

↓

[RxN - Balanced] 2Mg (s) + 2HCl (aq) → 2MgCl (aq) + H₂ (g)

[Given] 3.25 mol Mg

[Solve] x g HCl

Step 2: Identify Conversions

[RxN] 2 mol Mg → 2 mol HCl

[PT] Molar Mass of H - 1.01 g/mol

[PT] Molar Mass of Cl - 35.45 g/mol

Molar Mass of HCl - 1.01 + 35.45 = 36.46 g/mol

Step 3: Stoich

1. [S - DA] Set up:                                                                                                 $\displaystyle 3.25 \ mol \ Mg(\frac{2 \ mol \ HCl}{2 \ mol \ Mg})(\frac{36.46 \ g \ HCl}{1 \ mol \ HCl})$
2. [S - DA] Multiply/Divide [Cancel out units]:                                                    $\displaystyle 127.61 \ g \ HCl$

Step 4: Check

Follow sig fig rules and round. We are given 3 sig figs.

127.61 g HCl ≈ 128 g HCl