Convert the given amounts using the relationships from example two. Be sure to pay attention to the significant digits: 1. 25 g of elemental iron to moles of elemental iron, Fe. 2. 15.6 moles of carbon monoxide to grams of carbon monoxide, CO. 3. 125 g of sodium suffide to moles of sodtum sumde, Nas.S. 4. 1.25 moles of copper(ii) sulfide to grams of copperii) sulfide, CuS. 5. \( 3.34 \times 10^{24} \) Tormula units iron(il) nitrate to moles of iron(1) nitrate Fe(NO) ja 6. 1.345 grams of iron (III) nitrate to moles of iron(ili) nitrate Fe(NO) 7. 2.25 grams of glucose to molecules of ghoose \( \mathrm{CH}, \mathrm{O}_{5} \) 8. 375 grams of oxygen to moles of oxygen, \( \mathrm{O}_{2} \)

Sure, let's convert each of the given amounts with attention to significant digits. ### 1. **25 g of Elemental Iron to Moles of Iron (Fe)** - **Molar Mass of Fe:** ≈ 55.845 g/mol - **Calculation:** \[ \text{Moles of Fe} = \frac{25\, \text{g}}{55.845\, \text{g/mol}} \approx 0.4475\, \text{mol} \] - **Rounded (2 significant digits):** **0.45 mol Fe** --- ### 2. **15.6 Moles of Carbon Monoxide to Grams of CO** - **Molar Mass of CO:** C (12.01 g/mol) + O (16.00 g/mol) = 28.01 g/mol - **Calculation:** \[ \text{Mass of CO} = 15.6\, \text{mol} \times 28.01\, \text{g/mol} \approx 436.9\, \text{g} \] - **Rounded (3 significant digits):** **437 g CO** --- ### 3. **125 g of Sodium Sulfide to Moles of Sodium Sulfide (Na₂S)** - **Molar Mass of Na₂S:** (2 × Na, 22.99 g/mol) + S (32.07 g/mol) = 78.05 g/mol - **Calculation:** \[ \text{Moles of Na}_2\text{S} = \frac{125\, \text{g}}{78.05\, \text{g/mol}} \approx 1.601\, \text{mol} \] - **Rounded (3 significant digits):** **1.60 mol Na₂S** --- ### 4. **1.25 Moles of Copper(II) Sulfide to Grams of CuS** - **Molar Mass of CuS:** Cu (63.55 g/mol) + S (32.07 g/mol) = 95.62 g/mol - **Calculation:** \[ \text{Mass of CuS} = 1.25\, \text{mol} \times 95.62\, \text{g/mol} \approx 119.525\, \text{g} \] - **Rounded (3 significant digits):** **119.5 g CuS** --- ### 5. **\( 3.34 \times 10^{24} \) Formula Units of Iron(II) Nitrate to Moles of Fe(NO₃)₂** - **Avogadro's Number:** \( 6.022 \times 10^{23} \) units/mol - **Calculation:** \[ \text{Moles of Fe(NO}_3)_2 = \frac{3.34 \times 10^{24}}{6.022 \times 10^{23}\, \text{units/mol}} \approx 5.535\, \text{mol} \] - **Rounded (3 significant digits):** **5.54 mol Fe(NO₃)₂** --- ### 6. **1.345 Grams of Iron(III) Nitrate to Moles of Fe(NO₃)₃** - **Molar Mass of Fe(NO₃)₃:** Fe (55.845 g/mol) + 3 × NO₃ (62.01 g/mol each) = 241.875 g/mol - **Calculation:** \[ \text{Moles of Fe(NO}_3)_3 = \frac{1.345\, \text{g}}{241.875\, \text{g/mol}} \approx 0.00556\, \text{mol} \] - **Rounded (4 significant digits):** **5.56 × 10⁻³ mol Fe(NO₃)₃** --- ### 7. **2.25 Grams of Glucose to Molecules of Glucose (C₆H₁₂O₆)** - **Molar Mass of C₆H₁₂O₆:** (6 × C, 12.01 g/mol) + (12 × H, 1.008 g/mol) + (6 × O, 16.00 g/mol) = 180.16 g/mol - **Calculation:** \[ \text{Moles of Glucose} = \frac{2.25\, \text{g}}{180.16\, \text{g/mol}} \approx 0.0125\, \text{mol} \] \[ \text{Number of Molecules} = 0.0125\, \text{mol} \times 6.022 \times 10^{23}\, \text{molecules/mol} \approx 7.53 \times 10^{21}\, \text{molecules} \] - **Rounded (3 significant digits):** **7.53 × 10²¹ molecules C₆H₁₂O₆** --- ### 8. **375 Grams of Oxygen to Moles of O₂** - **Molar Mass of O₂:** 32.00 g/mol - **Calculation:** \[ \text{Moles of O}_2 = \frac{375\, \text{g}}{32.00\, \text{g/mol}} \approx 11.71875\, \text{mol} \] - **Rounded (3 significant digits):** **11.7 mol O₂** --- **Summary of Conversions:** 1. **0.45 mol Fe** 2. **437 g CO** 3. **1.60 mol Na₂S** 4. **119.5 g CuS** 5. **5.54 mol Fe(NO₃)₂** 6. **5.56 × 10⁻³ mol Fe(NO₃)₃** 7. **7.53 × 10²¹ molecules C₆H₁₂O₆** 8. **11.7 mol O₂**