chem chapter test
6)How many molecules are there in 2.1 mol CO 2 ? A) 1.26 x 10 24 molecules B) 3.49 x 10 -24 molecules C) 2.53 x 10 24 molecules D) 3.79 x 10 24 molecules E) 1.05 x 10 -23 molecules
1.26 x 10 24 molecules
36) What is the volume, in liters, of 6.8 mol of Kr gas at STP? A) 13,000 L B) 25 L C) 3.3 L D) 152 L E) 0.30 L
152 L
55) What is the mass of oxygen in 250 g of sulfuric acid, H 2 SO 4 ? A) 163 g B) 16 g C) 41 g D) 3.9 g E) 0.65 g
163 g
4)How many atoms are there in 5.7 mol of hafnium? A) 3.43 x 10 24 atoms B) 1.06 x 10 22 atoms C) 1.06 x 10 23 atoms D) 3.43 x 10 23 atoms E) 6.02 x 10 23 atoms
3.43 x 10 24 atoms
41) What is the volume (in liters at STP) of 2.50 mol of carbon monoxide? A) 3.1 L B) 9.0 L C) 56 L D) 70 L E) 560 L
56 L
18)Avogadro's number is _____. A) the weight of a carbon atom B) 6.02 x 10 23 C) a mole D) a dozen E) dependent on what is measured
6.02 x 10 23
2)How many moles of tungsten atoms are there in 4.8 x 10 25 atoms of tungsten? A) 1.3 x 10 -1 moles B) 8.0 x 10 -1 moles C) 1.3 x 10 -2 moles D) 80 moles E) 8.0 x 10 2 moles
80
64) The ratio of carbon atoms to hydrogen atoms to oxygen atoms in a molecule of dicyclohexyl maleate is 4 to 6 to 1. What is the molecular formula of this substance if its gram formula mass is 280 g? A) C 4 H 6 O B) C 12 H 18 O 3 C) C 8 H 12 O 2 D) C 20 H 30 O 5 E) C 16 H 24 O 4
C 16 H 24 O 4
74) Which of the following is NOT a true statement concerning empirical and molecular formulas? A) The molecular formula of a compound can be some whole-number multiple of its empirical formula. B) Several compounds can have the same empirical formula, but have different molecular formulas. C) The molecular formula of a compound can be the same as its empirical formula. D) If the molecular formula of hydrogen peroxide is H 2 O 2 , its empirical formula is HO. E) The empirical formula of a compound can be triple its molecular formula.
The empirical formula of a compound can be triple its molecular formula.
20)The gram atomic masses of any two elements contain the same number of _____. A) ions B) atoms C) grams D) anions E) milliliters
atoms
47) Which of the following conversion processes does NOT depend upon the gram formula mass of a substance? (volume refers to the volume of a gas at STP.) JUST TYPE THE LETTER ANSWER A) mass → mole → volume B) mass → mole → number of representative particles C) volume → mole → number of representative particles D) number of representative particles → mole → mass E) volume → mole → mass
c
42) The volume of one mole of substance is 22.4 L at STP for all _____. A) liquids B) elements C) solids D) gases E) compounds
gases
48) For which of the following conversions does the value of the conversion factor depend upon the formula of the substance? A) mass of any substance to moles B) volume of gas (STP) to moles C) number of particles to moles of gas (STP) D) density of gas (STP) to gram formula mass E) moles of any substance to number of particles
mass of any substance to moles
1)What is the SI unit for measurement of number of particles in a substance ? A) kilogram B) ampere C) candela D) mole E) Kelvin
mole
16)Avogadro's number of representative particles is equal to one _____. A) liter B) kelvin C) mole D) gram E) kilogram
mole
57) What information is needed to calculate the percent composition of a compound? A) the density of the compound and Avogadro's number B) the weight of the sample to be analyzed and its density C) the weight of the sample to be analyzed and its molar volume D) the formula of the compound and the gram atomic mass of its elements E) the formula of the compound and its density
the formula of the compound and the gram atomic mass of its elements
