The answer is 6.88.
Solution:
We can calculate for the percent composition of CaCl2 by mass by dividing the mass of the CaCl2 solute by the mass of the solution and then multiply by 100. The total mass of the resulting solution is the sum of the mass of CaCl2 solute and the mass of water solvent. Therefore, the percent composition of CaCl2 by mass is
% by mass = (mass of the solute / mass of the solution)*100
= mass of solute / (mass of the solute + mass of the solvent)*100
= (27.7 g CaCl2 / 27.7g + 375g) * 100
= 6.88
Answer: D
Explanation:
They form from Coal under high high pressure and many many years
<span><u><em>Answer:</em></u>
All of the above
<u><em>Explanation:</em></u>
Vertebrates are a class of creatures falling under kingdom "<u>Animalia</u>" that are characterized by the presence of an internal skeleton composed of bones.
<u>Vertebrates are characterized by the following:</u>
1- presence of internal skeleton
2- developed brain
3- the presence of an advanced nervous system connected to the brain
4- presence of muscles that allow movement
5- protective skin
6- circulation of blood in the bodies in the vessels
Comparing the mentioned characteristics with the options given, we will find that the most suitable answer is: <u>"all of the above"</u>.
Hope this helps :)</span>
Step 1: write the equation:
P₄(s) + 6F₂(g) → 4PF₃(g)
Step 2: Molar mass of P₄ = 30.97 g/mol × 4 = 123.88 g/mol
Step 3: Number of moles of phosphorus
n = m/M
n = 8.5 g/123.88g/mol
n = 0.07 moles
Step 4: 0.07 × 12 = 0.84 moles of fluorine.
Fluorine is diatomic gas so we multiplied the number of moles by 12.
Step 5: To find the mass of fluorine we multiply the number of moles with the molar mass.
Mass of fluorine = 0.84 × 228
= 191.52 grams.
Answer: placing coefficients
Explanation: In a balanced chemical equation, the total number of atoms of each element present is the same on both sides of the equation. Stoichiometric coefficients are the coefficients required to balance a chemical equation. These are important because they relate the amounts of reactants used and products formed.
