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
Answer:
Mass = 55.52 g
Explanation:
Given data:
Number of atoms of Li = 4.81×10²⁴ atom
Number of grams = ?
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
For Li:
4.81×10²⁴ atom × 1 mol / 6.022 × 10²³ atom
8 moles
Mass in gram:
Mass = number of moles × molar mass
Mass = 8 mol × 6.94 g/mol
Mass = 55.52 g
Answer:
The correct answer is - option D. the boiling point of solution A will be lower than the boiling point of solution B
Explanation:
Colligative properties such as a decrease in the freezing point of the solution, increase in the boiling point of substance, decrease in Lowering of vapor pressure, and other properties depend upon the number of molecules only.
In the given solution the equal amount of two solutions are mixed that is 50 grams however due to the difference in the molecular mass so the atoms present in both solution A and B will be different. It is known that the number of atoms of a substance is inversely proportional to the molecular mass of the particular substance.
As it is given that Solution B has a low molecular mass which means it has a high number of atoms that means its boiling point will be higher than solution A.
Answer:
Solar power
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Explanation:
Answer:
The answer is D.
Explanation:
Volume (V) = l x w x h
V = 4 x 5 x 1.2
V = 20 x 1.2
V = 24
Density = Mass/Volume or D = M/V
D = 85,000/24
D = 3541.66666666
