Answer:
Example
0.5 mol of sodium hydroxide is dissolved in 2 dm3 of water. Calculate the concentration of the sodium hydroxide solution formed.
Concentration =
Concentration = 0.25 mol/dm3
Volume units
Volumes used in concentration calculations must be in dm3, not in cm3. It is useful to know that 1 dm3 = 1000 cm3. This means:
divide by 1000 to convert from cm3 to dm3
multiply by 1000 to convert from dm3 to cm3
For example, 250 cm3 is 0.25 dm3 (250 ÷ 1000). It is often easiest to convert from cm3 to dm3 before continuing with a concentration calculation.
Question
100 cm3 of dilute hydrochloric acid contains 0.02 mol of dissolved hydrogen chloride. Calculate the concentration of the acid in mol/dm3.
Reveal answer
Converting between units
The relative formula mass of the solute is used to convert between mol/dm3 and g/dm3:
to convert from mol/dm3 to g/dm3, multiply by the relative formula mass
to convert from g/dm3 to mol/dm3, divide by the relative formula mass
Remember: the molar mass is the Ar or Mr in grams per mol.
Example
Calculate the concentration of 0.1 mol/dm3 sodium hydroxide solution in g/dm3. (Mr of NaOH = 40)
Concentration = 0.1 × 40
= 4 g/dm3
<u>Answer:</u> The temperature at which the food will cook is 219.14°C
<u>Explanation:</u>
To calculate the final temperature of the system, we use the equation given by Gay-Lussac Law. This law states that pressure of the gas is directly proportional to the temperature of the gas at constant pressure.
Mathematically,
where,
are the initial pressure and temperature of the gas.
are the final pressure and temperature of the gas.
We are given:
Putting values in above equation, we get:
Converting the temperature from kelvins to degree Celsius, by using the conversion factor:
Hence, the temperature at which the food will cook is 219.14°C
Answer:
See explanation for detailed solution
Explanation:
The balanced reaction equation is Ba(NO3)2 + 2HSO3NH2 → Ba(SO3NH2)2 + 2HNO3
Number of moles of Ba(NO3)2 = 1.4 g/ 261.337 g/mol = 5.36 × 10^-3 moles
From the reaction equation;
1 mole of Ba(NO3)2 yields 1 mole of Ba(SO3NH2)2
5.36 × 10^-3 moles of Ba(NO3)2 yields 5.36 × 10^-3 moles of Ba(SO3NH2)2
For HSO3NH2
Number of moles = 2.4g/97.10 g/mol =0.0247 moles
2 moles of HSO3NH2 yields 1 mole of Ba(SO3NH2)2
0.0247 moles of HSO3NH2 yields 0.0247 ×1/2 = 0.0137 moles
Hence, Ba(NO3)2 is the limiting reactant
The theoretical yield of Ba(SO3NH2)2 is 5.36 × 10^-3 moles × 329.4986 g/mol = 1.766 g
b)
Number of moles = mass/ molar mass
Molar mass = mass/ number of moles
Molar mass = 1.6925 g/5.36 × 10^-3 moles = 315.76 g
Answer:
2 is the correct answer maybe
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