Coffee is a mixture because it is a mixture of many compounds
Answer:
d) The dilution equation works because the number of moles remains the same.
Explanation:
Let’s say that you have 1 mol of a solute in I L of solution. The concentration is 1 mol·L⁻¹. and <em>M</em>₁<em>V</em>₁ = 1 mol.
Now, you dilute the solution to a volume of 2 L. You still have 1 mol of solute, but in 2 L of solution. The new concentration is 0.5 mol·L⁻¹.
The volume has doubled, but the volume has halved, and <em>M</em>₂<em>V</em>₂ = 1 mol.
b) <em>Wrong</em>. The molar concentration changes on dilution.
c) <em>Wrong</em>. The volume changes on dilution.
a) <em>Wrong</em>, although technically correct, because if the moles don’t change, the mass doesn’t change either. However, the formula <em>M</em>₁<em>V</em>₁ has units mol·L⁻¹ × L = mol. Thus, in the formula, it is moles that are constant.
Answer: -2.79°C
Explanation:
Supposing complete ionization:
Li2SO4 → 2 Li{+} + SO4{2-} [three ions]
(0.50 m Li2SO4) x 3 = 1.50 m ions
(1.50 m) x (1.86 °C/m) = 2.79°C change
0°C - 2.79°C = -2.79°C
Is that supposed to say 200/2.00??
