Answer: The kilograms of water must evaporate from 8kg of a 25% salt solution to produce 40% salt solution is 3 kg.
Explanation:
According to the ratio and proportion:

where,
= concentration of ist solution = 25%
= mass of ist solution = 8 kg
= concentration of second solution = 40%
= mass of second solution = ? kg


Thus the final solution must have a mass of 5 kg , i.e (8-5)= 3 kg of mass must be evaporated.
Therefore, the mass that must be evaporated from 8kg of a 25% salt solution to produce 40% salt solution is 3 kg.
Answer:
The gas obeys Boyle’s law and the value of
both are equal to 40.0 atm L.
Explanation:
Initial volume of the gas = 
Initial pressure of the gas = 
Final volume of the gas = 
Final pressure of the gas = 
This law states that pressure is inversely proportional to the volume of the gas at constant temperature.

The equation given by this law is:








The gas in the cylinder is obeying Boyle's law.
The gas obeys Boyle’s law and the value of
both are equal to 40.0 atm L.
Formula:

Given:
Density=3.4
Volume=500.0
Plug them into the formula:
Final answer: 1700g
Answer:
270g
Explanation:
Given parameters:
Concentration of NaOH = 1.5M
Volume = 4.5L
Unknown
Mass of NaOH added = ?
Solution:
To solve the problem, we need to find the number of moles of the NaOH first;
Number of moles = concentration x volume
Number of moles = 1.5 x 4.5 = 6.75mol
Now;
Mass = Number of moles x molar mass
Molar mass of NaOH = 23 + 16 + 1 = 40g/mol
Mass = 6.75 x 40 = 270g
C=2.41 g/L
m(NaCl)=0.291 g
c=m(NaCl)/v
v=m(NaCl)/c
v=0.291/2.41= 0.1207 L = 120.7 mL