Answer:
32 g Cu
Explanation:
1 mol Cu -> 63.5 g
0.5 mol Cu ->x
x=(0.5 mol *63.5 g)/1 mol x= 32 g Cu
Answer: 167 g
Explanation:
1) The depression of the freezing point of a solution is a colligative property ruled by this equation:
ΔTf = i × m × Kf
Where:
ΔTf is the decrease of the freezing point of the solvent due to the presence of the solute.
i is the Van't Hoof factor and is equal to the number of ions per each mole of solute. It is only valid for ionic compounds. Here the solute is not ionice, so you take i = 1
Kf is the molal freezing constant and is different for each solvent. For water it is 1.86 m/°C
2) Calculate the molality (m) of the solution
ΔTf = i × m × Kf ⇒ m = ΔTf / ( i × Kf) = 5.00°C / 1.86°C/m = 2.69 m
3) Calculate the number of moles from the molality definition
m = moles of solute / kg of solvent ⇒ moles of solute = m × kg of solvent
moles of solute = 2.69 m × 1.00 kg = 2.69 moles
4) Convert moles to grams using the molar mass
molar mass of C₂H₆O₂ = 62.07 g/mol
mass in grams = number of moles × molar mass = 2.69 moles × 62.07 g/mol = 166.97 g ≈ 167 g
1. You can use Avogadro’s number, 6.022x10^23 atoms/mole, to answer this one.
(3.311x10^24/6.022x10^23) = 5.498 moles of substance
2. H2O has a formula weight approximately equal to 18 grams. Dividing the given amount by the formula weight of water will tell us the number of moles present.
126/18 = 7 moles H2O
5.75g
Explanation:
Given parameters:
Number of atoms = 1.505 x 10²³atoms
let us find the number of moles and mass of this atom.
Solution:
The mole is convenient unit for reporting measurements in chemistry. It allows us to make mathematical calculations:
one mole of substance contains 6.02 x 10²³atoms
Number of moles of Na given = 
= 0.25moles
Mass of Na atom given = number of moles x molar mass
Molar mass of Na= 23g/mole
Mass of Na = 0.25 x 23 = 5.75g
learn more:
Number of moles brainly.com/question/1841136
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