<span>lower than the boiling point of water
</span>
Note that
The heating value of standard coal is about 30,080 kJ/kg
1 L of water has a mass of 1.0 kg
The mass of 15 L of water = 15 kg.
The latent heat of vaporization of water is about 2260 kJ/kg,
The energy required to boil 15 L of water is
(2260 kJ/kg)*(15 kg) = 33900 kJ
The mass of coal required to provide this energy is
(33900 kJ)/(30080 kJ/kg) = 1.127 kg
Because 1 kg = 2.205 lb, the mass of coal required is
(1.127 kg)*(2.205 lb/kg) = 2.485 lb
Answer: 2.49 lb (nearest hundredth)
<span>An atom has 16 protons and 17 neutrons. What is the chemical symbol for the atom? Consult the periodic table.
Question 8 options:
A.33Cl This would be correct.
B.32S
C.33S
D.32Cl
</span>
Answer: V₂ = 37.71mL
Explanation: To determine the new volume of Helium gas, use the Combined Gas Law, which states the following relationship among pressure, volume and temperature:
where index 1 relates to the initial state of the gas and index 2 to the final state of the gas.
Temperature is in Kelvin, so:
T = °C + 273
For this situation, standard pressure is 1 atm. Temperatures will be:
T₁ = 20 + 273 = 293 K
T₂ = 91 + 273 = 364 K
Solving:
37.71
The new volume of He gas is 37.71 mL.
