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An element with mass 590 grams decays by 19.5% per minute. How much of the element is remaining after 15 minutes, to the nearest 10th of a gram?
1.Calculate the Molarity of a solution that contains 20.0 g NaCl in 0.30 L of solution.
2.Calculate the mass in grams of lithium nitrite of 120. mL of 0.500 M solution.
Describe how to prepare the solution.
3 Write the molecular, ionic and net ionic equations for the reactions in 26 and 27 between the following. If
there is no net ionic equation, write “no net ionic equation”:
potassium carbonate and sodium nitrate
Which of the following 1.00 m solutions has the highest boiling temperature?
a) Na2S
b) LiNO3
c) (NH4)3PO4
d) sucrose
Of the following solutions, ................ has the highest freezing temperature and
.................... has the lowest freezing temperature? Your answer should include two
letters in the correct order.
a) 5.0 m KCl
b) 3.0 m LiNO3
c) 2.0 m (NH4)3PO4
d) sucrose
30 .......................The freezing point depression constant, Kf of H2O = 1.86 oC/ m-1
The boiling point elevation constant, Kb of H2O = 0.52 oC oC/ m
Calculate the boiling temperature of a solution of 2.00 m AlCl3
Cobalt-60, with a half-life of 5.3 years, has a number of
applications, including medical therapy and the sterilization
of medical tools. Determine the mass of a 50 g sample that
would remain after
(a) 6 months
(b) 5 years
The central atom in the iodite ion, IO2 - , is surrounded by
[1] 1 single bond, 1 double bond and 2 lone pairs of electrons.
[2] 3 bonding pairs and 1 unshared pair of electrons.
[3] 1 bonding pair and 3 unshared pairs of electrons.
[4] 2 double bonds and no unshared pairs of electrons.
[5] 4 bonding pairs and 4 lone pairs of electrons.
An example of a compound that contains an atom with an expanded octet of electrons is [1] NaBF4
[2] NH4Cl
[3] SF4
[4] NaClO4
[5] BF3
Which of the following compounds contains both ionic and covalent bonds?
[1] ClF
[2] SO2
[3] NaCl
[4] SO3
[5] NaCN
Which of the following sets of quantum numbers is not allowed?
[1] n = 3, l = 1, ml = -1, ms = + ½
[2] n = 2, l = 1, ml = 0, ms = + ½
[3] n = 3, l = 0, ml = 0, ms = + ½
[4] n = 2, l = 2, ml = -1, ms = - ½
[5] n = 2, l = 1, ml = -1, ms = - ½
All of the following statements about the quantum numbers are true except
[1] n has integral values from 1 to ∞.
[2] l has values from 1 to ∞.
[3] ml has 2l + 1 possible values
[4] ml has values of –l to +l including zero.
[5] ms has values of +½ and -½.
Write an executable program in C++ to display an array of 6 rows and 2 colums, using a double line comment to display "computer programming"
Which statement is wrong?
[1] The atomic weight of carbon is about 12.
[2] The most stable ion of lithium is Li+ .
[3] A phosphorus atom is larger than an antimony atom.
[4] The radius of a sodium atom is larger than that of a sodium cation.
[5] Oxygen has a less negative electron affinity than fluorine.
