General Chemistry
Improve your experience by picking them
Consider two identical flasks at STP, one contains nitrogen gas and the other contains argon gas. Which of the following is a method to distinguish the two without opening the flasks?
At 15.0°C, a gas occupies a volume of 35.0 L and has a pressure of 136 atm. Calculate the volume (in L) it occupies at STP.
A newly discovered planet has a surface temperature of about 970 K and a pressure of 65 Earth atmospheres. These conditions define "STP" on this planet. Calculate the standard molar volume (in L) of gas on this planet.
Ammonia can be produced from the reaction of hydrogen gas and nitrogen gas at 500°C with a presence of a catalyst.
i. Calculate the moles of air needed to react with 1.5 mol of hydrogen gas given that air is 78.0% N2 by volume.
ii. Determine the volume (in L) of this air occupies at STP.
Butane gas (C4H10) is used as fuel for portable gas stoves. Calculate the volume (in L) of CO2 gas formed at STP when butane is combusted in a 10.0 L reaction vessel with a pressure of 3.15 atm at 25.0°C. The balanced reaction equation is as follows:
2 C4H10(g) + 13 O2(g) → 8 CO2(g) + 10 H2O(l)
(a) 28.9 L
(b) 703 L
(c) 115 L
(d) 352 L
Calculate the molar mass of a gas if its density at STP is 1.827 g/L.
The reaction between NO2 and H2 gas produces NH3 and H2O gas.
2 NO2 (g) + 7 H2 (g) → 2 NH3 (g) + 4 H2O (g)
In a particular reaction, NO2 gas (23.1 L, 783 torr, 68.0 °C) was mixed with H2 gas (24.8 L, 731 torr, 75.0 °C) which produced 4.67 L of NH3 gas at STP. Calculate the % yield of the reaction.
Consider CH4 and N2 which have molar volumes of 24.4 L at STP. Is there an expected increase or decrease in molar volume if the gases cooled to -200°C?
Consider CH4 and N2 which have molar volumes of 24.4 L at STP. If the densities of CH4 and N2 at -160°C are 0.00175 g/cm3 and 0.00305 g/cm3, calculate the molar volume at this temperature.
A compound used as a preservative is made up only of C, H, O, and Na. At STP, a sample of the compound weighing 100 mg was burned with excess oxygen. After the reaction is complete, 108.88 mL of CO2 and 38.88 mL of H2O were produced. In a separate analysis, it was found that the sample contains 15.96 mg of Na. Determine the molecular formula of the preservative.
Compare the number of particles of Cl2 and Kr at STP if both gas are in separate 2-L flasks.
A sample of Ne gas has a volume of 3.60 L at a pressure of 1.4 atm and a temperature of 20 ºC. Determine the volume of the Ne sample at STP.
Compare the density of Cl2 and Kr at STP if both gas are in separate 2-L flasks.
Calculate the moles of gas present if it has a volume of 60.5 L at STP.
Vehicular impacts trigger the chemical reaction NaN3(s) → Na(s) + N2(g) [unbalanced], which inflates air bags. Calculate the moles of NaN3 required to inflate a 10.5 L air bag at STP.
The mass of 150 mL of a gaseous hydrocarbon, determined at STP, is 0.174 g. The same hydrocarbon is analyzed and discovered to contain 92.24% C and 7.76% H by mass. Deduce the molecular formula of the compound.
Determine the density (in g/L) of Ne using the molar volume of a gas at STP.
At 22°C, a 2.75-L flexible flask contains N2, He, and Ne with the partial pressures of 0.295 atm for N2, 0.162 atm for He, and 0.535 atm for Ne.
(a) What is the total pressure in atm?
(b) What is the volume in liters at STP occupied by He and Ne if the N 2 is removed selectively?
The definition of standard conditions (STP) is
At STP, a sample of N2 gas occupies a volume of 672 mL. What is the volume occupied by N2 gas at 155°C at a pressure of 368 torr?
Rank the following gases in order of decreasing (largest to smallest ) density at STP: Kr, N2, Cl2, F2
At STP, what is the volume occupied by 33.5 g of argon gas?
At STP, calculate the mass of phosphine (PH3) that can be formed from the reaction of 42.5 g phosphorus and 96.0 L of hydrogen gas.
P4(s) + H2(g) ⟶ PH3(g) [unbalanced]
What is the molar mass of a gas if 285 mL of the gas weighs 2.33 g at STP?
What would be the density of oxygen, O2, at each condition?
a) STP
b) 1.56 atm and 66.0°C
Answer in grams per liter.
Ozone can oxidize copper in the reaction Cu(s) + O3(g) → CuO(s) + O2(g). Calculate the mass of Cu required to form 120.0 mL of O2 at STP.
Hydrogen gas (a potential future fuel) can be formed by the reaction of methane with water according to the equation:
CH4(g) + H2O(g) → CO( g) + 3 H2(g)
In a particular reaction, 25.5 L of methane gas (measured at a pressure of 732 torr and a temperature of 25 °C) mixes with 22.8 L of water vapor (measured at a pressure of 702 torr and a temperature of 125 °C). The reaction produces 26.2 L of hydrogen gas at STP. What is the percent yield of the reaction?
Automobile airbags inflate following a serious impact. The impact triggers the chemical reaction:
2 NaN3(s) → 2 Na(s) + 3 N2(g)
If an automobile airbag has a volume of 18.2 L, what mass of NaN3 (in g) is required to fully inflate the airbag upon impact? Assume STP conditions.