Percentage by mass is the mass of NaF present in 100 g of the solution.
the percentage by mass of NaF is 23.4 %
this means that in 100 g of solution, mass of NaF present is 23.4 g
the number of moles of NaF present - 1.33 mol
mass of NaF - 1.33 mol x 42 g/mol = 55.9 g
when there's 23.4 g of NaF - mass of solution is 100 g
therefore when there's 55.9 g of NaF - mass of solution is 100 / 23.4 x 55.9
= 239 g
mass of solution required is 239 g
Answer:
The balanced half-reaction for the reduction of dichromate ion to chromium ion in acidic aqueous solution:

Explanation:
The reaction :

Balancing of reaction in an acidic medium:
Step 1: Balance the atoms in the reaction:

Step 2: Balance oxygen atom by adding water on the side where no oxygen or less oxygen atom is present;

Step 3: Balance the hydrogen atom by adding hydrogen ions on the side where water is absent:

Step 4: Now balance charge by adding electrons on the side where more positive charge is present

The balanced half-reaction for the reduction of dichromate ion to chromium ion in acidic aqueous solution:

Answer:
Explanation:
All chemical changes requires a substantial amount of energy. Depending on the type of reaction, the energy of reactants and products differs.
In an exothermic chemical change where heat is always given off to the surroundings, the energy of the product is less than that of reactants.
For endothermic changes, the surrounding becomes colder at the end of the reaction. This implies that the heat energy of the product is higher than that of the reactants.
Answer:
Genes
Explanation:
The genes are the basic unit of hereditary which are a part of chromosomes that are passed from parents to their offspring.
Genes are responsible for the propagation of hereditary features. They are usually located on the chromosome.
Genes are made up of protein molecules.
Each parent passes down a copy of their gene which are inherited by the offspring and they determine a character state.
They generally make up the genotype.
Answer: [A]: "<span><span>two atoms, both the same element, bonded together</span>".
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