Answer:
The percent by mass of 3.55 g NaCl dissolved in 88 g water is 3.88%
Explanation:
When a solute dissolves in a solvent, the mass of the resulting solution is a sum of the mass of the solute and the solvent.
A percentage is a way of expressing a quantity as a fraction of 100. In this case, the percentage by mass of a solution is the number of grams of solute per 100 grams of solution and can be represented mathematically as:
In this way it allows to precisely establish the concentration of solutions and express them in terms of percentages.
In this case:
- mass of solute: 3.55 g
- mass of solution: 3.55 g + 88 g= 91.55 g
Replacing:
Percent by mass= 3.88%
<u><em>The percent by mass of 3.55 g NaCl dissolved in 88 g water is 3.88%</em></u>
If the atom is neutral (meaning, not charged) the number of electron is equal to the number of protons. The mass number of an atom is the sum of the number of proton and the number of neutrons. From the given above, the mass number of gallium is 31 + 39. The answer is letter D. 70.
Answer:
The correct option is the last option
Explanation:
The chemical reaction provided in the question is a double-displacement reaction which is an exothermic reaction (which is the reason for the release of heat). An example of a double displacement reaction and exothermic reaction is the neutralization reaction illustrated below.
HCl + NaOH ⇒ NaCl + H₂O
From the law of conservation of energy, energy can neither be created nor destroyed, hence the total energy in a given system should ordinarily be the same (in the reactants and products), however <u>when energy is released in a reaction (as in the case with an exothermic reaction), it shows there are more bond energy in the reactants than in the products and it is the excess energy that is been released into the atmosphere.</u>
