Answer:
1,620 J.
Explanation:
- The amount of heat added to a substance (Q) can be calculated from the relation:
<em>Q = m.c.ΔT.</em>
where, Q is the amount of heat released from ethanol cooling,
m is the mass of ethanol (m = 60.0 g),
c is the specific heat of ethanol in the liquid phase, since the T is cooled below the boiling point and above the melting point (c = 1.0 J/g °C),
ΔT is the temperature difference (final T - initial T) (ΔT = 43.0 °C – 70.0 °C = - 27.0 °C).
<em>∴ Q = m.c.ΔT</em> = (60.0 g)(1.0 J/g °C)(- 27.0 °C) = - 1620 J.
<em>The system releases 1620 J.</em>
Answer:
0.4033 M is the concentration of the sodium hydroxide solution.
Explanation:
Mass of potassium hydrogen phthalate = 2.023 g
Molar mass of potassium hydrogen phthalate = 204.22 g/mol
Moles of potassium hydrogen phthalate :
= 

According to reaction, 1 mole of potassium hydrogen phthalate reacts with 1mole of NaOH. Then 0.009906 moles of potassium hydrogen phthalate will recat with:
of NaOH
Moles of NaOH = 0.009906 mol
Volume of NaOH solution = 24.56 mL = 0.02456 L

![[NaOH]=\frac{0.009906 mol}{0.02456 L}=0.4033 M](https://tex.z-dn.net/?f=%5BNaOH%5D%3D%5Cfrac%7B0.009906%20mol%7D%7B0.02456%20L%7D%3D0.4033%20M)
0.4033 M is the concentration of the sodium hydroxide solution.
It describes how, when particles/mc/elements react, despite forming different substances the mass is neither created nor destroyed but only converted.