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Given 4Ga(s) + 3O2(g) ? 2Ga2O3(s), what mass of gallium oxide could be prepared from 5.00 g of gallium metal?
lewis dot structure of :
barium and nitrogen
aluminum and fluorine
calcium and sulfur
N2 O4
SO4^2-
1.Using a glass syringe, a scientist draws exactly 25.5 cm3 of dry oxygen at 20.0 ̊C
from a metal cylinder. She needs to heat the oxygen for an experiment, so she places
the syringe in an oven at 65.0 ̊C and leaves it there for 30 min. Assuming the
atmospheric pressure remains the same, what volume will the oxygen occupy?
2. The gas in the can of hair spray is initially at 24 °C and 360 kPa, and the can has
a volume of 350 mL. If the can is left in a car that reaches 50 °C on a hot day, what
is the new pressure in the can?
3. A sample of gas has a volume of 15.0 mL at a pressure of 13.0 psi. Determine the
pressure of the gas at a volume of 7.5 mL.
How many grams are there in 3.3 x 10^23 molecules of N2l6
How many grams are there in 4.5 moles of Ba(NO2)2
How many grams are there in 1.0 x 10^24 molecules of BCl3
How many moles are there in 2.0 x 10^19 molecules of CCl4
4. C-14 has a half-life of 5730 years and its activity in a wood just cut down from a tree of 15.3 disintegrations/min/g carbon. How old is a sample of a wooden artifact which gives 5 disintegrations/min/g carbon? (10 points)
3. Phosphorus-32 is used in biochemical studies to follow the pathway taken by metabolites. Its half-life is 14.3 days. A vial
containing 10 microgram of P-32 is accidentally spilled into a sink. (5 points each)
a. How long will it take P-32 in the drain to exhibit 68% of its original activity?
b. How many atoms of P-32 remain in the sink after 755 days?
2. One neutron and a new isotope, X, is formed when Bi-209 is bombarded with Ni-64. The isotope then goes through a
series of alpha particle emission. (4 points each)
a. Write the nuclear symbol for the isotope formed
b. Write the nuclear symbol for the isotope formed after the third alpha particle emission.
