Answer:
C
Explanation:
In thermodynamics, a exothermic system looses heat to the surroundings while an endothermic system absorbs heat from the surroundings.
A system is a part the universe marked off by a specified boundary. The contents of the cup constitutes the system in this case.
The region of space outside the system is called the surroundings. Hence everything outside the cup constitutes the surroundings.
Answer: 733 kcal
Explanation:
According to a system used to calculate the available energy of foods, we have the following data:
- protein has 4 kcal/g
- carbohydrates has 4 kcal/g
- fat has 9 kcal/g
- alcohol has 7 kcal/g
So, we are told Jhon and his wife's dinner has:
- 55 g of carbohydrates
- 36 g of protein
- 27 g of fat
- 18 g of
Now we have to multiply these values by the kilocalories:
- (55 g of carbohydrates)(4 kcal/g)=220 kcal
- (36 g of protein)(4 kcal/g)=144 kcal
- (27 g of fat)(9 kcal/g)=243 kcal
- (18 g of alcohol)(7 kcal/g)=126 kcal
Then we have to sum all, giving the following result:
<h2>733 kcal</h2>
The boiling point of oxygen is higher than nitrogen's boiling
The reason the boiling point of O2 is higher is not because of increased van der Waals interactions, but simple physics. The mass of a molecule of O2 is greater than that of a molecule of N2, so the molecule of O2 traveling at a speed sufficient to break out of the liquid phase has a greater kinetic energy than an analogous N2 molecule.
The net effect is that more energy must be distributed throughout a sample of O2 to achieve a given vapor pressure (in this case equal to atmospheric pressure) than for a sample of N2. More energy means greater temperature.
Answer: First, here is the balanced reaction: 2C4H10 + 13O2 ===> 8CO2 + 10H2O.
This says for every mole of butane burned 4 moles of CO2 are produced, in other words a 2:1 ratio.
Next, let's determine how many moles of butane are burned. This is obtained by
5.50 g / 58.1 g/mole = 0.0947 moles butane. As CO2 is produced in a 2:1 ratio, the # moles of CO2 produced is 2 x 0.0947 = 0.1894 moles CO2.
Now we need to figure out the volume. This depends on the temperature and pressure of the CO2 which is not given, so we will assume standard conditions: 273 K and 1 atmosphere.
We now use the ideal gas law PV = nRT, or V =nRT/P, where n is the # of moles of CO2, T the absolute temperature, R the gas constant (0.082 L-atm/mole degree), and P the pressure in atmospheres ( 1 atm).
V = 0.1894 x 0.082 x 273.0 / 1 = 4.24 Liters.
Explanation:
