A deep breath of air has a volume of 1.05 L at a pressure of 740 torr and body t
ID: 545635 • Letter: A
Question
A deep breath of air has a volume of 1.05 L at a pressure of 740 torr and body temperature which is 37°C. Calculate the number of molecules in the breath. I. 2. At 36 °C and 1.00 atm, a gas occupies a volume of 0.600 L. How many liters will it occupy at 0 °C and 0.205 atm and at STP? Calcium hydride reacts with water to form hydrogen gas according to the following equation: 3. CaHa + 2 H2O H2 + Ca(OH) 2 How many grams of CaH2 are needed to produce 10.0 L of H2 gas if the partial pressure of H2 is 740 torr at 23 C? A gas evolved during the fermentation of sugar was collected at 22.5 °C and 702 mmHg. After purification its volume was found to be 25.0 L. How many moles of gas were collected? 4, Gases are sold in large cylinders for laboratory use. What pressure in atmospheres will be exerted by 2500 g of oxygen gas (O2) when stored at 22 °C in a 40.0 L cylinder? 5.Explanation / Answer
1)
Given:
P = 740.0 torr
= (740.0/760) atm
= 0.9737 atm
V = 1.05 L
T = 3.7 oC
= (3.7+273) K
= 276.7 K
find number of moles using:
P * V = n*R*T
0.9737 atm * 1.05 L = n * 0.08206 atm.L/mol.K * 276.7 K
n = 4.5*10^-2 mol
number of molecules = number of mol * Avogadro’s number
= 4.5*10^-2 mol * 6.022*10^23 molecules/mol
= 2.71*10^22 molecules
Answer: 2.71*10^22 molecules
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