1) Which statement below is incorrect if any?
a)when gas is at STP, the pressure of the gas is at 1.00 atm.
b)when a gas is at STP, the temperature of the gas is 25 degrees celsius
c)at STP the molar volume of a gas is 22.4L
d)at STP the molar volume of all gases are the same
e) all the statements above are correct
I chose answer D as the correct one.
2)For an ideal gas, which pairs of variables are directly proportional to each other(if all other factors remain constant)?
a) P and T
b) P and V
c) V and T
d) n and V
I chose P&T, V&T, and n&V.
Are these correct?
2 is ok. 1 is not correct.
What is STP?
1 atm
273 K (zero C)
1) The correct answer is e) all the statements above are correct. At STP (Standard Temperature and Pressure), the pressure of gas is indeed 1.00 atm, the temperature is 25 degrees celsius, and the molar volume of a gas is 22.4L. Additionally, the molar volume of all gases is the same at STP.
2) The correct pairs of variables that are directly proportional to each other in an ideal gas, while keeping all other factors constant, are:
- b) P (pressure) and V (volume)
- c) V (volume) and T (temperature)
- d) n (number of moles) and V (volume)
So, your choices of P&T, V&T, and n&V are correct.
For the first question, let's go through each statement and determine which one is incorrect:
a) "When gas is at STP, the pressure of the gas is at 1.00 atm." This statement is correct. At STP (Standard Temperature and Pressure), the pressure is defined to be exactly 1.00 atm.
b) "When a gas is at STP, the temperature of the gas is 25 degrees Celsius." This statement is incorrect. At STP, the temperature is actually 0 degrees Celsius (or 273.15 Kelvin).
c) "At STP, the molar volume of a gas is 22.4L." This statement is correct. At STP, the molar volume of any ideal gas is defined to be 22.4 liters per mole.
d) "At STP, the molar volume of all gases are the same." This statement is correct. At STP, the molar volume of any ideal gas is always 22.4 liters per mole, regardless of the gas's identity.
Therefore, option b) is the incorrect statement, as the temperature of a gas at STP is 0 degrees Celsius.
Now, let's move on to the second question:
a) "P and T" - This is correct. According to the Ideal Gas Law (PV = nRT), if pressure (P) is held constant, an increase in temperature (T) will result in an increase in volume (V).
b) "P and V" - This is correct. According to the Ideal Gas Law, if temperature (T) is constant, an increase in pressure (P) will result in a decrease in volume (V) and vice versa.
c) "V and T" - This is correct. As mentioned in the previous options, an increase in temperature (T) at constant pressure (P) will result in an increase in volume (V).
d) "n and V" - This is incorrect. The number of moles (n) of a gas does not directly affect the volume (V) of the gas.
Therefore, your choices for the second question (P&T, V&T) are correct, while your choice of n&V is incorrect.