Magnesium metal is added to excess acid to generate hydrogen gas, which is collected over water at 25.0°C (vapour pressure of wa
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<u>Answer:</u> The given sample of water is not safe for drinking.
<u>Explanation:</u>
We are given:
Concentration of fluorine in water recommended = 4.00 ppm
ppm is the amount of solute (in milligrams) present in kilogram of a solvent. It is also known as parts-per million.
To calculate the ppm of fluorine in water, we use the equation:
Both the masses are in grams.
We are given:
Mass of fluorine = (Conversion factor: 1 g = 1000 mg)
Mass of water = 5.00 g
Putting values in above equation, we get:
As, the calculated concentration is greater than the recommended concentration. So, the given sample of water is not safe for drinking.
Hence, the given sample of water is not safe for drinking.
Answer:
5.85 grams of NaCl should be added to 250 grams of water to make a 0.40 m solution.
Explanation:
Mass of NaCl =x
Molar mass of NaCl = 58.5 g/mol
Molality of the solution = 0.40 m
Mass of the solvent = 250 g = 0.250 kg (1g = 0.001 kg)
5.85 grams of NaCl should be added to 250 grams of water to make a 0.40 m solution.
The energy needed to raise the temperature of water from 22.0ºC to 90.0ºC is c. 28.4 kJ.
<h3>What is specific heat?</h3>The amount of energy needed to raise the temperature of one gram of a substance by one degree Celsius.
By the formula
Q is the heat
m is the mass
c is the specific heat
Now, c = 4.184 J/g.K
The change in temperature is 22.0 ºC to 90.0 ºC
Putting the value in the equation
Thus, the energy needed to raise the temperature of water from 22.0ºC to 90.0ºC is 28.4 kJ
Learn more about specific heat
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