Answer:

Explanation:
<u>Convert Atoms to Moles</u>
The first step is to convert atoms to moles. 1 mole of every substance has the same number of particles: 6.022 ×10²³ or Avogadro's Number. The type of particle can be different, in this case it is atoms of silver. Let's create a ratio using this information.

We are trying to find the mass of 8.23 ×10²³ silver atoms, so we multiply by that number.

Flip the ratio so the atoms of silver cancel. The ratio is equivalent, but places the other value with units "atoms Ag" in the denominator.


Condense into one fraction.


<u>Convert Moles to Grams</u>
The next step is to convert the moles to grams. This uses the molar mass, which is equivalent to the atomic mass on the Periodic Table, but the units are grams per mole.
Let's make another ratio using this information.

Multiply by the number of moles we calculated.

The moles of silver cancel out.



<u>Round</u>
The original measurement of atoms has 3 significant figures, so our answer must have the same. For the number we calculated, that is the ones place.
The 4 in the tenths place tells us to leave the 7 in the ones place.

8.23 ×10²³ silver atoms are equal to approximately <u>147 grams.</u>
<span>The density of the solution =1.05 g/ml.
</span><span>The total mass of the resulting solution is = 398.7 g (CaCl2 + water)
</span>
Find moles of CaCl2 and water.
Molar mass of CaCl2 = 110 (approx.)
Moles of CaCl2 = 23.7 / 110 = 0.22
so, moles of Cl- ion = 2 x 0.22 = 0.44 (because each molecule of CaCl2 will give two Cl- ions)
Moles of water = 375 / 18 = 20.83
Now, Mole fraction of CaCl2 = (moles of CaCl2) / (total moles)
total moles = moles of Cl- ions + moles of Ca2+ ions + moles of water
= 0.44 + 0.22 + 20.83
=21.49
So, mole fraction = 0.44 / (21.49) = 0.02
Guess what !!! density is not used. No need
Answer:
True
Explanation:
Stars are bright and enormous astronomical bodies that are located at a large distance from the earth. They are made up of the lightest gaseous elements namely hydrogen and helium. These hydrogen atoms undergo the reaction of nuclear fusion, which fuels the energy of the star and allows the star to shine, releasing a large amount of energy. They are located about trillions of miles away from the location of the earth, due to which they appear smaller in size.
Thus, the above-given statement is True.
The answer is B. Acid turns blue litmus paper to red
Answer:
3
Explanation:
2x5 is 10 then 13-10 is 3