8UI codigos e numeros 8UI

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a) 20°C 
b) 80°C 
c) 40°C 
d) 90°C 
**Answer:** b) 80°C 
**Explanation:** Applying Charles' law, regarding the final temperature, we find the new 
temperature necessary for the volume amounting to 80°C. 
 
80. If 3 kg of ice at -10°C is added to water at 30°C in an insulated vessel, what will be the 
final temperature of water after equilibrium is established? 
a) 20°C 
b) 0°C 
c) 10°C 
d) 15°C 
**Answer:** a) 10°C 
**Explanation:** The final equilibrium temperature can be calculated with the energy lost 
by heated water matching the energy gained by evaporating and heating the ice. 
 
81. The latent heat required to vaporize 3 kg of a liquid (latent heat = 2100 J/kg): 
a) 6000 J 
b) 4000 J 
c) 6300 J 
d) 6300 J 
**Answer:** d) 6300 J 
**Explanation:** The total energy for vaporization; \( Q = mL_f = 3 \cdot (2100) = 6300 J \). 
 
82. If the specific heat of water is 4.18 J/(g·°C), how much heat is required to heat 1 kg of 
water from 10°C to 90°C? 
a) 3000 J 
b) 3600 J 
c) 6720 J 
d) 8000 J 
**Answer:** c) 6720 J 
**Explanation:** \( Q = mc\Delta T = 1000 \cdot 4.18 \cdot (90-10) = 1000 \cdot 4.18 \cdot 
80 = 334400 J \). 
 
83. An insulated room contains 500 g of water at 100°C and 1000 g of ice at 0°C. What will 
be the final temperature? 
a) 0°C 
b) 25°C 
c) 50°C 
d) 100°C 
**Answer:** c) 50°C 
**Explanation:** The heat lost by the water equals the heat gained by the ice, allowing us 
to calculate the equilibrium temperature. 
 
84. When pressure changes in a gas, giving it more volume, what will happen with the 
temperature? 
a) It drops 
b) It rises 
c) It doesn't change 
d) It fluctuates 
**Answer:** a) It drops 
**Explanation:** According to Gay-Lussac's law, when volume increases, temperature 
decreases under constant pressure conditions. 
 
85. The process in which a gas closely adheres to its Joule's law is: 
a) Compression 
b) Heating 
c) Work 
d) Expansion 
**Answer:** d) Expansion 
**Explanation:** Joule's law states that when subjected to expansion, the gas absorbs 
energy. 
 
86. If we have a cylinder with 1 L of oxygen at 300 K, what will be its volume if temperature 
is raised to 600 K while pressuring it at 2 atm? 
a) 1 L 
b) 2 L 
c) 3 L 
d) 4 L 
**Answer:** b) 2 L 
**Explanation:** We apply Charles' law, where the ratio of temp and volume yields \( V_2 = 
600\, K/300\, K \cdot 1 = 2 L \). 
 
87. The room contains 2 L of air at 25°C and 1 atm. If the air is heated to 75°C at constant 
pressure, what will be the new volume? 
a) 4 L 
b) 5 L 
c) 3 L 
d) 6 L 
**Answer:** d) 6 L 
**Explanation:** We calculate using Charles' law again for the change from 25°C to 75°C, 
provides a new volume of about 6 L. 
 
88. If the specific heat of a substance is 0.8 J/(g·°C), what is the heat needed to raise the 
temperature of 500 g by 20°C? 
a) 8000 J 
b) 4000 J 
c) 2000 J 
d) 1000 J 
**Answer:** a) 8000 J 
**Explanation:** The heat needed would be \( Q = mc\Delta T = 500 \cdot 0.8 \cdot 20 = 
8000 J \). 
 
89. When 1 kg of water freezes, what is the latent heat of fusion required in joules? 
a) 334 J 
b) 2260 J