Answer:
Hạt nhân của nguyên tử X có điện tích là 30,4.10-19 culông. Tìm số p,e của nguyên tử X
Data:
solute: ethylene glicol => not ionization
molar mass of ethylene glicol (from internet) = 62.07 g/mol
solute = 400 g
solvent = water = 4.00 kg
m =?
ΔTf = ?
Kf = 1.86 °C/mol
Formulas:
m: number of moles of solute / kg of solvent
ΔTf = Kf*m
number of moles of solute = mass in grams / molar mass
Solution
number of moles of solute = 400 g / 62.07 g/mol = 6.44 moles
m = 6.44 mol / 4 kg = 1.61 m <-------- molality (answer)
ΔTf = 1.86 °C / m * 1.61 m = 2.99 °C <---- lowering if freezing point (answer)
The scientific notation of 420,000 is : 4.2 x 10 ^ 5
Answer:
to protect peoples teeth against cavities
Explanation:
i just know
Answer:
3.47 mol MnSO4
Explanation:
54.94 + 32.07 + (16 × 4) = 151.01g/mol MnSO4
542.32g / 151.01g/mol = 3.47 mol MnSO4
