How many grams of urea [(NH2)2CO] must be added to 400 g of
water to give...
How many grams of urea [(NH2)2CO] must be added to 400 g of
water to give a solution with a vapour pressure 2.50 mmHg less than
that of pure water at 30°C? (The vapour pressure of water at 30°C
is 31.8 mmHg.)
How
many grams of sucrose (C12H22O11) must be added to 477 g of water
to give a solution with a vapor pressure 0.555 mmHg less than that
of pure water at 20 degrees celsius? (The vapor pressure of water
at 20 degrees celsius is 17.5 mmHg).
You prepare a solution by adding 20.0 g Urea
[(NH2)2CO] to 125 g water at
25.0oC & vapor pressure 23.76 torr.
The solution vapor pressure
is 22.67 torr. Calculate the molecular weight of urea.
XH2O = ________
moles H2O = ________
Xsolute = ________ moles
urea = ________ molar mass = ________
Urea (NH2)2CO is prepared by reactign
ammonia with carbon dioxide. The byproduct is water. 637.2g of
ammonia are reacted with 787.3g of carbon dioxide.
A) write a balanced equation
B) Determine which of the reactants (ammonia or carbon dioxide)
is a limiting reactant. Show calculations to support your
choice
C) Which of the two reactants should you use to calculate the
theoretical yield (=the maximum amount possible) of urea. Explain
why
Urea, chemical formula (NH2)2CO, is used for fertilizer and many
other things. Calculate the number of N, C, O, and H atoms in 1.78
× 104 g of urea. Enter your answers in scientific notation.
How many grams of CaCl2 should be added to 50.0 g of water to
make a solution in which the mole fraction of Cl1- is 0.150?
***I understand how this question should be set up, I am
confused about a certain part of the set up. The correct set up is
as follows:
0.150 = (2n mol Cl-)/ (3n mol ions + 2.78 mol of H2O) and solve
for n;
I do not understand why the ratio within the problem...
Calculate the amount of water (in grams) that must be added to
(a) 9.00 g of urea [(NH2)2CO] in the preparation of a 8.10 percent
by mass solution: (b) 28.9 g of MgBr2 in the preparation of a 2.90
percent mass solution:
How many grams of water at 25°C must be added to a Dewar flask
(isolated system) containing 20 g of ice at -5°C to
satisfy the conditions in (a) through (d)? Compute the entropy
change in each case.
Predict the sign of ΔS in each case before doing the
calculation.
a) The final temperature is -2°C; all the water freezes.
b) The final temperature is 0°C; half the water freezes
c) The final temperature is 0°C; half the ice melts...
How many grams of sodium formate (68.01 g/mol) must be added to
2.0L of 0.10 M formic acid (Ka=1.77 x 10^-4) to form a buffer whose
pH is 3.50? (Assume that the addition of the salt does not change
the volume of the solution).