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2 years ago

What is the only nonmetal with four valence electrons?.

Chemistry

1 answer:

mamaluj [8]2 years ago

7 0

Answer:

Carbon

Explanation:

I just finished this and that's what I got from my periodic table.

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Find the total number of atoms in a sample of cocaine hydrochloride, c17h22clno4, of mass 23.0 mg .

Nataliya [291]

From the periodic table:
mass of carbon = 12 grams
mass of hydrogen = 1 gram
mass of nitrogen = 14 grams
mass of oxygen = 16 grams
mass of chlorine = 35.5 grams
Therefore,
molar mass of c17h22clno4 = 17(12) + 22(1) + 35.5 + 14 + 4(16) = 339.5 grams

number of moles = mass / molar mass
number of moles = (23*10^-3) / (339.5)
number of moles = 6.77 * 10^-5 moles

number of atoms = number of moles * Avogadro's number
number of atoms = 6.77*10^-5 * 6.022*10^-23
number of atoms = 4.079 * 10^-27 atoms

3 0

3 years ago

The fuel used in many disposable lighters is liquid butane, C4H10. Butane has a molecular weight of 58.1 grams in one mole. How

labwork [276]

First convert grams to moles using molar mass of butane that is 58.1 g

3.50g C4H10 x (1 mol C4H10)/(58.1g C4H10) = 0.06024 mol C4H10 

Now convert moles to molecules by using Avogadro’s number

0.06024 mol C4H10 x (6.022x10^23 molecules C4H10)/(1 mol C4H10) = 3.627x10^22 molecules C4H10

And there are 4 carbon atoms in 1 molecule of butane, so use the following ratio:

3.627 x 10^22 molecules C4H10 x (4 atoms C)/(1 molecule C4H10)
= 1.45 x 10^23 atoms of carbon are present

7 0

3 years ago

Read 2 more answers

Determine which choice is an example of an endothermic process.

klemol [59]

Answer:

D. Baking bread

Explanation:

In this process, energy is absorbed and in an endothermic process energy is absorbed too.

6 0

3 years ago

The mass fractions of a mixture of gases are 15 percent nitrogen, 5 percent helium, 60 percent methane, and 20 percent ethane wi

cricket20 [7]

Answer:

See explanation

Explanation:

Number of moles of each gas is

Nitrogen = 15/28 = 0.536 kmoles

Helium = 5/4 = 1.25 kmoles

Methane = 60/16 = 3.75 kmoles

Ethane = 20/30 = 0.67 kmoles

Total number of moles = 0.536 kmoles + 1.25 kmoles + 3.75 kmoles + 0.67 kmoles = 6.206 kmoles

Mole fraction of each gas;

Nitrogen = 0.536 kmoles/6.206 kmoles = 0.086

Helium = 1.25 kmoles/6.206 kmoles = 0.201

Methane = 3.75 kmoles/6.206 kmoles =0.604

Ethane = 0.67 kmoles/6.206 kmoles =0.108

Partial pressure of each gas;

Nitrogen = 0.086 * 1200 kPa = 103.2 kPa

Helium = 0.201 * 1200 kPa = 241.2 kPa

Methane = 0.604 * 1200 kPa = 724.8 kPa

Ethane = 0.108 * 1200 kPa = 129.6 kPa

Apparent specific heat at constant pressure;

Cp = (0.15 * 1.039) + (0.05 * 5.1926) + ( 0.6 * 2.2537) + (0.2 * 1.7662)

Cp = 2.12 KJ Kg-1 K-1

Cv = Cp- Ru/M

Cv= 2.12 - 8.314/16.12 = 1.604 KJ Kg-1 K-1

8 0

2 years ago

How many grams are in 2.3 x 10^23 atoms of silver

ozzi

There are 41.1984 grams of silver in 2.3x 10^23 atoms of silver

4 0

3 years ago