How many oxygen atoms are in 2.30 g of quartz?
2 answers:
Answer:
4.61 * 10²² oxygen atoms
Explanation:
- Quartz is the common name of a silicon mineral, SiO₂.
- To solve the problem, we need to calculate the molar mass (MM) of quartz:
MM = AtomicMass of Si + 2 * AtomicMass of O
MM = 28.08 + 2 * 16
MM = 60.08 g/mol
- Then we can calculate how many moles of quartz are in 2.30 g:
2.30 g * = 0.0383 mol
- Then we use <em>Avogadro's number </em>calculate the number of oxygen atoms in 0.0383 mol of SiO₂, keeping in mind the number of O per quartz molecule:
0.0383 mol SiO₂ * = 4.61 * 10²² atoms of O
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Answer:
194.6 mL of SO₂
Explanation:
The reaction that takes place is:
P₄S₃ + 6O₂(g) → P₄O₁₀ + 3SO₂(g)
<u>To solve this problem we need to use PV=nRT</u>, so first let's convert the given units:
- 23.8 °C → 23.8 + 273.15 = 296.95 K
- 747 torr → 747/760 = 0.983 atm
We need to calculate V, so in order to do that we calculate n, using the mass of the reactant (P₄S₃):
0.576 g P₄S₃ * = 7.85 * 10⁻³ mol SO₂ = n
- Now we calculate V:
PV=nRT
0.983 atm * V = 7.85 * 10⁻³ mol * 0.082 atm·L·mol⁻¹·K⁻¹ * 296.95 K
V = 0.1946 L
- Finally we convert L into mL:
0.1946 * 1000 = 194.6 mL