Chem Exam
How many molecules of O2 are present in a 3.90L flask at a temperature of 273K and a pressure of 1.00atm? Use 6.022×1023 mol−1 for Avogadro's number.
1.05×1023molecules
An aqueous solution at 25∘C has a hydronium ion concentration of 9.7×10−5 M. What is the hydroxide ion concentration of the solution?
1.0×10−10 M
A sample of a gas has a pressure of 1.26bar at 58.0∘C. What is the pressure of the gas at 118∘C?
1.49bar
What is the osmotic pressure of a 0.50L solution that contains 0.15g of benzene (C6H6) at 298.15K? Use R=0.08206L atmmol K for the ideal gas constant.
0.094 atm
What is the temperature of a 1.59L flask containing 0.175mol of Ne at a pressure of 1.09atm?
121K
A gas mixture contains 0.150 mol of oxygen (O2) gas and 0.211 mol of argon (Ar) gas. What is the mole fraction of O2 in the mixture?
0.416
The molecular mass of water (H2O) is 18.02amu. What is the molar mass of water?
18.02g/mol
What is the stoichiometric factor between N2 and NO in the following balanced chemical equation? N2+O2⟶2NO
1N2:2NO
A sample of a gas has a pressure of 1.01atm when the volume is 256mL. What is the pressure of the gas when the volume is 118mL?
2.19atm
Balance the following equation:H2O2⟶H2O+O2
2H2O2⟶2H2O+O2
In the chemical equation 2A+3B⟶C+4D, how many molecules of C can form if 6molecules of A react?
3 molecules
What is the molarity of CaCl2 when 1.92mol of CaCl2 is dissolved in water to form 515mL of solution?
3.73M
How many moles of retinol (C20H30O), a form of vitamin A, are in a 0.125g sample of retinol?
4.36×10−4mol
Suppose a solution is described as concentrated. Which of the following statements can be concluded? A.The solution is supersaturated. B.The solution is not supersaturated. C.The solute is insoluble. D.None of the above
D.None of the above
What is the hydronium ion concentration of a solution at 25∘C with a pOH of 4.70?
5.0×10−10 M
Sodium chloride is also known as table salt. The chemical formula of sodium chloride is NaCl. Calculate the molar mass of sodium chloride.
58.44g/mol
A sample of a gas has a pressure of 248mm Hg when the volume is 1.05L. What is the pressure of the gas when the volume is 3.98L?
65.4mm Hg
A solution of KOH contains 15.0g of KOH in 185.0g water. What is the mass percent of KOH in the solution?
7.50%
What is the pH of a solution with a pOH of 6.2?
7.8
A gas mixture contains 0.150 mol of oxygen (O2) gas, 0.419mol of nitrogen (N2) gas. and 0.211 mol of argon (Ar) gas in a 0.250L flask at 298K. What is the total pressure of the mixture
76.3atm
A solution of a compound in water conducts electricity, turns litmus red, and has a sour taste. What compound might be in the solution?
C3H5(COOH)3
According to the kinetic molecular theory, where does the pressure exerted by a gas in a container come from?
Pressure results from collisions between the constantly moving gas molecules and the container walls.
Non-polar solutes are soluble in which of the following?
non-polar solvents
A patient has symptoms including increased breathing rate, numbness, muscle spasms, and nausea. The blood pH is checked and found to be 7.5 and CO2 pressure is 37 torr. The patient most likely has what condition?
respiratory alkalosis
Which is a possible example of species that can comprise a buffer solution?
H2PO−4 and H3PO4
What is the formula for the conjugate acid of dihydrogen phosphate, H2PO−4?
H3PO4
Which is a neutralization reaction?
HCl(aq)+NaOH(aq)⟶NaCl(aq)+H2O(l)
In the equation C1V1=C2V2, what does C represent?
Concentration
What will happen to the pressure of a gas if its absolute temperature triples (increases by a factor of three) while the number of moles of gas and the volume are held constant?
The pressure will triple (increase by a factor of three).
What will happen to the volume of a gas if its absolute temperature triples (increases by a factor of three) as the amount of gas and the pressure are held constant?
The volume will triple (increase by a factor of three).
Of the following, which is a characteristic of nonelectrolytes?
They produce no ions when dissolved in water.
Balance the following equation: X2+Y2⟶XY3
X2+3Y2⟶2XY3
Which of the following is the term for the reaction between two molecules of the same neutral substance to produce an ion pair?
autoionization
Is the following reaction endothermic or exothermic? H2(g)+I2(g)+energy(heat)⟶2HI(g)
endothermic
Is the following reaction endothermic or exothermic? 2Al(s)+Fe2O3(s)⟶2Fe(s)+Al2O3(s)+energy(heat)
exothermic
A solution that a patient needs for medical treatment needs to be __________ with blood cells.
isotonic