The number of moles of KF needed to prepare the solution is 3 moles
<h3>What is molarity?</h3>
Molarity is defined as the mole of solute per unit litre of solution. Mathematically, it can be expressed as:
Molarity = mole / Volume
<h3>How to determine the mole of KF </h3>
- Volume = 2500 mL = 2500 / 1000 = 2.5 L
- Molarity = 1.2 M
- Mole of KF =?
Molarity = mole / Volume
1.2 = mole of KF / 2.5
Cross multiply
Mole of KF = 1.2 × 2.5
Mole of KF = 3 moles
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We know, Given mass = Molar mass * Number of moles.
A.) <span>1.25 mol CaF</span>₂
Number of moles = 1.25
Molar mass = 78
So, Mass = 78 * 1.25 = 97.5 g
B.) 3.4 mol (NH₄)₂SO₄
Number of moles = 3.4
Molar mass = 132
Mass = 3.4 * 132 = 448.8 g
Hope this helps!
Answer:
2,400,000 torr (3 s.f.)
Explanation:
Convert the pressure from Pascal to atm first:

3.20 ×10⁸ Pa
= [(3.20 ×10⁸) ÷101325] atm
= 3158.2 atm (5 s.f.)
Convert atm to torr:

3158.2 atm
= (3158.2 ×760) torr
= 2400000 torr (3 s.f.)