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3 years ago

What is the atomic mass for Helium (He)? Question 5 options: 8 2 3 4

1 answer:

3 0

It is 2 because if you have a chart that shown all the elements at the top left corner it would show a number and that is the atomic number

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10. Liquid changing to gas only at the surface is called

mina [271]

Answer:

Evaporation

Explanation:

Though it doesn't require high temperatures to do so

3 0

3 years ago

Hydrocarbons separated by fractional distillation of petroleum can be cracked to make

lana66690 [7]

Answer:

c.hg cannot be cracked for fractional distillation as there is only one of each

Explanation:

8 0

3 years ago

HELP ASAP ITS TIMED!!!

Tpy6a [65]

Answer:

C would be the right answer

5 0

3 years ago

Read 2 more answers

Determine the molality of a solution of methanol dissolved in ethanol for which the mole fraction of methanol is 0.135. Give you

Alja [10]

<u>Answer:</u> The molality of the solution is 0.11 m

<u>Explanation:</u>

We are given:

Mole fraction of methanol = 0.135

This means that 0.135 moles of methanol is present in 1 mole of a solution

Moles of ethanol = 1 - 0.135 = 0.865 moles

To calculate the mass for given number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

Moles of ethanol = 0.865 moles

Molar mass of ethanol = 46 g/mol

$0.865mol=\frac{\text{Mass of ethanol}}{46g/mol}\\\\\text{Mass of ethanol}=(0.865mol\times 46g/mol}=39.79g$

To calculate the molality of solution, we use the equation:

$Molality=\frac{m_{solute}\times 1000}{M_{solute}\times W_{solvent}\text{ (in grams)}}$

Where,

$m_{solute}$ = Given mass of solute (methanol) = 0.135 g

$M_{solute}$ = Molar mass of solute (methanol) = 32 g/mol

$W_{solvent}$ = Mass of solvent (ethanol) = 39.79 g

Putting values in above equation, we get:

$\text{Molality of methanol}=\frac{0.135\times 1000}{32\times 39.79}\\\\\text{Molality of methanol}=0.106m\approx 0.11m$

Hence, the molality of the solution is 0.11 m

6 0

3 years ago

A HOMOGENEOUS LIQUID THAT CANNOT BE SEPARATED INTO ITS COMPONENTS BY DISTILLATION BUT CAN BE DECOMPOSED BY ELECTROLYSIS IS CLASS

nata0808 [166]

Answer:

ELEMENTS

Explanation:

CUZ AN A

ELEMENT IS A GROUP OF ATOMS THAT CANNOT BE BROKEN DOWN BY ANY CHEMICAL OR PHYSICAL MEAN

7 0

2 years ago