Answer:
The answer to your question is 88.7 ml
Explanation:
Data
Volume = ?
Concentration of NaOH = 0.142 M
Volume of H₂C₄H₄O₆ = 21.4 ml
Concentration of H₂C₄H₄O₆ = 0.294 M
Balanced chemical reaction
2 NaOH + H₂C₄H₄O₆ ⇒ Na₂C₄H₄O₆ + 2H₂O
1.- Calculate the moles of H₂C₄H₄O₆
Molarity = moles/volume
Solve for moles
moles = Molarity x volume
Substitution
moles = 0.294 x 21.4/1000
Result
moles = 0.0063
2.- Use proportions to calculate the moles of NaOH
2 moles of NaOH ------------------ 1 moles of H₂C₄H₄O₆
x ------------------ 0.0063 moles
x = (0.0063 x 2) / 1
x = 0.0126 moles of NaOH
3.- Calculate the volume of NaOH
Molarity = moles / volume
Solve for volume
Volume = moles/Molarity
Substitution
Volume = 0.0126/0.142
Result
Volume = 0.088 L or 88.7 ml
Answer:
The heat needed to boil 1 gallon of water is 81,490.62 Joules.
Explanation:

Where:
Q = heat absorbed or heat lost
c = specific heat of substance
m = Mass of the substance
ΔT = change in temperature of the substance
We have :
Volume of water = V = 1 gal = 4546.09 mL
Density of water , d= 1 g/mL
mass of water = m = d × V = 1g/mL × 4546.09 mL = 4546.09 g
Specific heat of water = c = 1 Cal/g°C
ΔT = 100°C - 25°C = 75 °C
9 (boiling pint of water is 100°C)
Heat absorbed by the water to make it boil:

1 calorie = 4.184 J

The heat needed to boil 1 gallon of water is 81,490.62 Joules.