Answer:
20.5 × 10²³ molecules of He
Explanation:
Given data:
Number of moles of He = 3.40 mol
Number of molecules of He = ?
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,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
For 3.40 moles of He:
3.40 mol × 6.022 × 10²³ molecules
20.5 × 10²³ molecules of He
Answer:
The final volume of the copper (ii) sulfate solution = 93.6 mL
<em>Note: The question is incomplete. The complete question is given below:</em>
<em>A chemist must dilute 37.0 mL of 602. mM aqueous copper(II) sulfate (Cuso4) solution until the concentration falls to 238. mM. He'll do this by adding distilled water to the solution until it reaches a certain final volume. Calculate this final volume, in milliliters. Be sure your answer has the correct number of significant digits.</em>
Explanation:
Using the equation of dilution, C₁V₁ = C₂V₂
where C₁ = initial concentration
V₁ = initial volume
C₂ = final concentration
V₂ = final volume
For the aqueous solution of copper (ii) sulfate
C₁ = 602 mM; V₁ = 37.0 mL; C₂ = 238 mM; V₂ = ?
Making V₂ subject of formula
V₂ = C₁V₁/C₂
V₂ = (602 mM * 37.0 mL)/238 mM
V₂ = 93.6 mL
Therefore, the final volume of the copper (ii) sulfate solution = 93.6 mL
Answer:
2H+(aq) + 20H(aq) → H20(l)
Explanation:
The reaction between sulphuric acid and calcium hydroxide is a neutralization reaction. Neutralization reaction involves the reaction of hydrogen ions and hydroxide ions to form water. This has been shown in the equation.
The number of water molecules formed depends on the number of moles of hydrogen and hydroxide ions present in the compounds. There are two hydrogen ions in sulphuric acid and two hydroxide ions in calcium hydroxide. Hence, two moles of water is formed.
Answer : The correct option is, (3) titration
Explanation :
Titration : It is a laboratory process where we have to use the volume of a solution of known concentration to determine the concentration of unknown solution.
Distillation : It is a process in which we used to separate a pure liquid from the mixture of the liquids based on the different boiling points.
Fermentation : It is a chemical process in which the the bacteria, an organism or yeast converts the carbohydrate into an alcohol or an acid.
Transmutation : It is a process in which the nucleus of a chemical elements changes into another.
Hence, the correct option is, (3) titration