you are given the mass of an element, you use the periodic table to find its molar mass, and multiply the given mass by the reciprocal of the molar mass. This is Mass → Moles . Once you have moles, multiply by Avogadro's number to calculate the number of atoms. This is Moles → Atoms

7 0

3 years ago

An automobile travels 34.0 miles per gallon. How many kilometers does it travel per liter of gasoline? Use these equalities: 1 m

lisov135 [29]

To convert on unit to another unit, a conversion factor is needed to multiply in the value given. For the value given above, we have to convert it from miles per gallon to kilometers per liter. The factors to be used are:

1 mile = 1.61 kilometers;
1 gallon = 3.79 liters.

<span>34.0 miles / gallon ( 1.61 kilometers / 1 mile ) ( 1 gallon / 3.79 L ) = 14.44 kilometer / liter</span>

7 0

4 years ago

Camphor (C10H16O) melts at 179.8°C, and it has a particularly large freezing-point-depression constant, Kf= 40.0ºC/m. When 0.186

Usimov [2.4K]

Answer:

Molar mass for the unknown solute is 109 g/mol

Explanation:

Freezing point depression is the colligative property that must be applied to solve the question.

T°F pure solvent - T°F solution = Kf . m

Let's analyse the data given

Camphor → solvent

Unknown solute → The mass we used is 0.186g

T°F pure solvent = 179.8°C and T°F solution = 176.7°C.

These data help us to determine the ΔT → 179.8°C - 176.7°C = 3.1°C

So we can replace → 3.1°C = 40°C/m . m

m = 3.1°C / 40 m/°C → 0.0775 mol/kg

We have these moles of solute in 1kg of solvent, but our mass of camphor is 22.01 g (0.02201 kg).

We can determine the moles of solute → molality . kg

0.0775 mol/kg . 0.02201 kg = 1.70×10⁻³ moles

Molar mass → mass (g) / moles → 0.186 g / 1.70×10⁻³ mol = 109 g/mol

3 0

4 years ago

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