Answer:
Maybe (yes/no)
Explanation:
Cause some theories about the end of the universe. The fate of the universe is determined by its density. The preponderance of evidence to date, based on measurements of the rate of expansion and the mass density, favors a universe that will continue to expand indefinitely, resulting in the "Big Freeze" scenario below.
Answer: 2.4 ml
Solution :
Molar mass of 
= 17 g/mole
Given,: 28% w/w of solution means 28 g of ammonia in 100 g of solution.
Mass of solution = 100 g
Now we have to calculate the volume of solution.
Molarity : It is defined as the number of moles of solute present in one liter of solution.
where,
n = moles of solute 
= volume of solution in liter = 0.11 L
Now put all the given values in the formula of molarity, we get
Using molarity equation:
Answer:
6.022 x 10²³; it is a conversion factor between moles and number of particles
Explanation:
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,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole of hydrogen = 6.022 × 10²³ atoms of hydrogen
238 g of uranium = 1 mole of uranium = 6.022 × 10²³ atoms of uranium
By taking ions:
62 g of NO⁻₃ = 1 mole of NO⁻₃ = 6.022 × 10²³ ions of NO⁻₃
96 g of SO₄²⁻ = 1 mole of SO₄²⁻ = 6.022 × 10²³ ions of SO₄²⁻
A solution (in this experiment solution of NaNO₃) freezes at a lower temperature than does the pure solvent (deionized water). The higher the
solute concentration (sodium nitrate), freezing point depression of the solution will be greater.
Equation describing the change in freezing point:
ΔT = Kf · b · i.
ΔT - temperature change from pure solvent to solution.
Kf - the molal freezing point depression constant.
b - molality (moles of solute per kilogram of solvent).
i - Van’t Hoff Factor.
First measure freezing point of pure solvent (deionized water). Than make solutions of NaNO₃ with different molality and measure separately their freezing points. Use equation to calculate Kf.
