2 years ago

Which element is a metalloid?

Chemistry

2 answers:

Naily [24]2 years ago

8 0

Answer:

helium Because it's in the 9th grade book

Andrews [41]2 years ago

3 0

Answer: B

Arsenic

Explanation:

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How many moles are in 5.5 x 10-23 molecules of H2O

masha68 [24]

Answer:

0.914moles

Explanation:

The number of moles in a substance can be got by dividing the number of atoms/molecules/particles by Avagadro's constant (6.02 × 10^23).

That is;

number of moles (n) = number of atom (nA) ÷ 6.02 × 10^23

According to this question, there are 5.5 x 10-23 molecules of H2O

n = 5.5 x 10^23 ÷ 6.02 × 10^23

n = 0.914 × 10^(23-23)

n = 0.914 × 10^0

n = 0.914 × 1

n = 0.914moles

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2 years ago

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3 years ago

According to Boyle's law, the volume of a gas is inversely proportional to its pressure at constant temperature.

meriva

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true

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3 years ago

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A man threw a Frisbee which weighs 3 kg with a velocity of 5 m/s. What is the KE in the system? *

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The answer would be 8 just took the test

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2 years ago

The vapor pressure of water at 65oC is 187.54 mmHg. What is the vapor pressure of a ethylene glycol (CH2(OH)CH2(OH)) solution ma

Pavlova-9 [17]

Answer:

173.83 mmHg is the vapor pressure of a ethylene glycol solution.

Explanation:

Vapor pressure of water at 65 °C= $p_o= 187.54 mmHg$

Vapor pressure of the solution at 65 °C= $p_s$

The relative lowering of vapor pressure of solution in which non volatile solute is dissolved is equal to mole fraction of solute in the solution.

Mass of ethylene glycol = 22.37 g

Mass of water in a solution = 82.21 g

Moles of water= $n_1=\frac{82.21 g}{18 g/mol}=4.5672 mol$

Moles of ethylene glycol= $n_2=\frac{22.37 g}{62.07 g/mol}=0.3603 mol$

$\frac{p_o-p_s}{p_o}=\frac{n_2}{n_1+n_2}$

$\frac{187.54 mmHg-p_s}{187.54 mmHg}=\frac{0.3603 mol}{0.3603 mol+4.5672 mol}$

$p_s=173.83 mmHg$

173.83 mmHg is the vapor pressure of a ethylene glycol solution.

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2 years ago