No of moles = given mass ÷ molecular mass
n = 55.98 ÷ (12+19×2+35.5×2)
Answer:
Francium (Fr)
Explanation:
Looking at the periodic table, Francium has 7 energy levels as it is in the 7th Period and is in the 1st Group (meaning it has one electron in the outermost shell) which suggests that it has one valence electron.
<em>Hope this helps and be sure to have a wonderful time ahead at Brainly! :D</em>
The formula for density is:
D = m/v
We can use the formula to figure out the mass because we already know two of the three values (we are given the density and volume), so we only have to solve for <em>m. </em>If we plug our given values into the formula, we get:
2.70 = m / 264
Now, all we need to do is solve for <em>m</em>. The goal is to get <em>m</em> on one side of the equation, and all we have to do is multiply each side of the equation by 264:
264 × 2.70 = (m÷264) × 264
264 × 2.70 = m
m = 712.8
The mass of the piece of aluminum is 712.8 grams.
<u>Answer:</u> The molality of solution is 0.740 m.
<u>Explanation:</u>
To calculate the mass of solvent (water), we use the equation:
Volume of water = 750 mL
Density of water = 1 g/mL
Putting values in above equation, we get:
To calculate the molality of solution, we use the equation:
Where,
= Given mass of solute 
= 100.0 g
= Molar mass of solute = 180 g/mol
= Mass of solvent (water) = 750 g
Putting values in above equation, we get:
Hence, the molality of solution is 0.740 m.
