Answer:
positive one (+1)
Explanation:
sodium having atomic mass is twenty three (23) and atomic number is eleven (11).
Sodium atom having only one electron in it's outer most shell and it is easy for atom to lose this electron from outer most shell to make itself stable.
So after losing this electron positive charge on the upper right side of the atom will occur with the number of electron lose that is Na+1 .
<span>8.278 g/mL
The definition of density is mass per volume. So what you need to do is divide the known mass by the known volume. So
1.663 g / 0.2009 mL = 8.27775 g/mL
But you also have to keep track of significant figures. Since both 1.663 and 0.2009 have 4 significant figures each, you need to round the result to 4 significant figures. So
8.27775 g/mL = 8.278 g/mL</span>
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>
Answer :
The molar mass of ibuprofen is, 206.29 g/mole.
The number of moles of ibuprofen in a single tablet is, 0.000969 moles
The number of moles of ibuprofen in four doses is, 0.007752 moles
Solution : Given,
Molar mass of carbon = 12.01 g/mole
Molar mass of hydrogen = 1.01 g/mole
Molar mass of oxygen = 15.99 g/mole
1) Now we have to calculate the molar mass of ibuprofen.
Molar mass of ibuprofen,
= 
The molar mass of ibuprofen = 206.29 g/mole
2) Now we have to calculate the moles of ibuprofen.
Formula used : 
Given : Mass of ibuprofen = 200 mg = 0.2 g (1 mg = 1000 g)

The moles of ibuprofen = 0.000969 moles
3) Now we have to calculate the number of moles of ibuprofen for four doses.
Number of tablets in one dose = 2
Total number of tablets in 4 doses = 4 × 2 = 8
Number of moles of ibuprofen in 8 tablets =
