In a presentation about measuring mass, one of your classmates states, "Two objects of the same size will always have the same m
2 answers:
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Answer:
1.155 moles of potassium nitrate are required to make 550 mL of a 2.1M solution.
Explanation:
In a mixture, the chemical present in the greatest amount is called a solvent, while the other components are called solutes.
Molarity is a unit of concentration of a solution and indicates the amount of moles of solute that appear dissolved in each liter of the mixture. In other words, the Molarity (M) or Molar Concentration is the number of moles of solute that are dissolved in a given volume.
The Molarity of a solution is determined by the following expression:
Molarity is expressed in units ().
In this case:
- Molarity= 2.1 M
- number of moles of solute= ?
- Volume= 550 mL= 0.550 L (being 1L=1000 mL)
Replacing:
Solving:
number of moles of solute= 2.1 M* 0.550 L
number of moles of solute= 1.155 moles
1.155 moles of potassium nitrate are required to make 550 mL of a 2.1M solution.
Answer:
0.012mol
Explanation:
1.
Given parameters:
Pressure in the balloon = 1.25atm
Volume of the balloon = 2.5L
Unknown:
Number of moles = ?
Solution:
We are going to used the combined gas law to solve this problem.
PV = nRT
P is the pressure
V is the volume
n is the number of moles
R is the gas constant = 0.082atmdm³mol⁻¹K⁻¹
Insert the parameters and solve;
1.25 x 2.5 = n x 0.082 x 285
n = 0.13mol
The number of moles is 0.13mol
2.
Given parameters:
Pressure = 16torr;
to atm is ;
760torr = 1atm
16torr = = 0.02atm
Volume = 12L
Temperature = 253K
Using the ideal gas law;
PV = nRT
0.02x12 = n x 0.082 x 253
n = 0.012mol