Answer:
1. 2090 J
2. 113,000J
3. 33,900J
4. -209.2 J
5. 2g
Explanation:
Note: specific heat capacity of water is 4.184 J/g°C.
1. The amount of heat can be calculated using the formula:
Q = m × c × ∆T
Q = 25 × 4.184 × (30 - 10)
Q = 104.6 × 20
Q = 2092 J
Q = 2090 J (nearest tens)
2. This question can be solved using the latent heat of vaporization of water. The latent heat of vaporization of a substance is the amount of heat required to convert a unit gram of a liquid into vapor without a change in temperature. The latent heat of vaporization of water per gram is:
2257 J/g
For 50grams of water, amount of heat that will be required will be: 50 × 2260
= 113,000J
3. For 15g of water, the amount of heat will be 15 × 2260 (latent heat of vaporization)
= 33,900J
4. Q = m × c × ∆T
Q = 5 × 4.184 × (40 - 50)
Q = 20.92 × (-10)
Q = -209.2 J
5. Q = m × c × ∆T
84 = m × 4.184 × (35 - 25)
84 = m × 4.184 × 10
84 = 41.84m
m = 84/41.84
m = 2.0076
m = 2g
