*PLEASE HELP!*
1) Which substance has a molar mass of 142 g?
A) MgCl2
B) AlCl3
C) P2O5
D) BaCl2
2)What did Amedeo Avogadro discover?
A) One mole of a substance contains 6.02×1023 particles.
B) Equal volumes of gases at the same temperature and pressure contain the same number of particles.
C) The mass of one mole of a substance is equal to its formula weight expressed in grams.
D) Equal volumes of gases at STP contain 6.02×1023 particles.
3) What is the volume of one mole of a diatomic gas at STP ?
A) 18.2 L
B) 20.0 L
C) 22.4 L
D) 44.8 L
4) You do an experiment in which you need 0.5 mole of tyrosine (C9H11NO3) .
How many grams must you weigh out?
A) 65 g
B) 90.5 g
C) 181 g
D) 272 g
5) For an experiment, you need to dissolve 0.05 mole of NaCl in one liter of water.
How much NaCl must you weigh out?
A) 0.14 g
B) 2.9 g
C) 5.9 g
D) 8.2 g
