Answer:
146 kJ
Explanation:
There are two heat flows in this question.
Heat lost on cooling + heat lost on solidifying = 0
q₁ + q₂ = 0
mCΔT + nΔHsol = 0
Data:
m = 575 g
C = 0.449 J·K⁻¹g⁻¹
T_i = 1825 K
T_f = 1811 K
ΔHsol = -13.8 kJ·mol⁻¹
Calculations:
(a) Heat lost on cooling
ΔT = T_f - T_i = 1811 K - 1825 K = -14 K
q₁ = mCΔT = 575 g × 0.449 J·K⁻¹g⁻¹ × (-14 K) = -361 J = -3.61 kJ
(b) Heat lost on solidifying
(c) Total heat lost
q = q₁ + q₂ = -3.61 kJ - 142.1 kJ = -146 kJ
The heat lost was 146 kJ.
Answer:
The most acidic solution had a pH of 3.27.
Explanation:
In order to solve this problem we need to keep in mind that the lower the pH of a solution is, the more acidic the solution is.
If among the pH readings across the measured breakfast drinks, the lowest one was 3.27 (as the problem tells us with the range), then that drink was the most acidic one.
Conversely, the least acidic one had a pH of 3.88.
Answer:
Explanation:
The pressure is constant, so we can use Charles' Law.
Data:
V₁ = 1.92 × 10³ L; T₁ = 20 °C
V₂ = ?; T₂ = 68 °C
Calculations:
(a) Convert temperatures to kelvins
T₁ = (20 + 273.15) K = 293.15 K
T₂ = (68 + 273.15) K = 341.15 K
(b) Calculate the volume
The new volume of the gas is .
Answer:
1.40 M [OH⁻]
Explanation:
This compound dissociates into 3 ions, but since we are asked about [OH⁻], it's only 2. Therefore, multiply the molarity of the solution by the number of ions that [OH⁻] dissociates into:
2 × 0.70 M = 1.40 M
Hope this helps! Sorry that you got a link. Those are getting really annoying
Answer:
Animal cells have centrosomes (or a pair of centrioles), and lysosomes, whereas plant cells do not. Plant cells have a cell wall, chloroplasts, plasmodesmata, and plastids used for storage, and a large central vacuole, whereas animal cells do not.
