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3 years ago

Please help me with this first one to answer gets brainlyest!!!!!!!!

Chemistry

1 answer:

Dmitriy789 [7]3 years ago

4 0

Question 1: Which of the following is true?

Answer:

Figure II and Figure IV are both compounds.

Explanation:

Compound is a substance which is formed by chemical reaction of different elements.

Example:

Water = H₂O = Which is made up of hydrogen and oxygen atoms.

Carbon Dioxide = CO₂ = Which is made up of carbon and oxygen atoms.

In given figures, Figure I and Figure III are not compounds because Figure I is containing a substance which is made up of same atoms like N₂, O₂, Cl₂ and Figure III is containing a substance which is made up of single monoatomic element like Ne, Kr, Xe gases.

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Question 2: Which of the following statement is true?

Answer:

The Figure is the Molecule and a Compound

Explanation:

Molecules are formed when two or more, either same or different atoms join chemically. While, compound is any substance which formed when two different atoms join together chemically.

In given figure, it can be seen that the particles are made up of two atoms. Hence, it is said to be a molecule. Also, the atoms which are forming the molecule are different in color means, they are different atoms therefore, it is also called as compound.

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Question 3: Which of the following list includes only molecules?

Answer:

Third List only include Molecules

Explanation:

Molecules are formed by the combination of two or more same or different atoms. In given options;

List 1 is containing a substance ( Mg ) which is existing in monoatomic form. It means we can exclude the first list.

List 2 is containing a substance ( Fe ) which is existing in monoatomic form. It means this list can also be excluded.

List 3 is containing all substances in molecular forms. Like NaCl made up of Na and Cl, N₂ made up of two nitrogen atoms and H₂O (water) made up of two hydrogen and one oxygen atoms.

List 4 is containing a substance ( He ) which is existing in monoatomic form. It means this list can also be excluded.

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The molecular structure of water contains two atoms of hydrogen and one atom of oxygen. When water reaches its boiling point and

Andrews [41]

It turns from a liquid to a gas

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3 years ago

Help please its science

Nookie1986 [14]

Answer: any answer choices

Explanation:

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3 years ago

A 200.0mL closed flask contains 2.000mol of carbon monoxide gas and 2.000mol of oxygen gas at the temperature of 300.0K. How man

max2010maxim [7]

Answer:

There will react 0.400 moles of oxygen.

Explanation:

Step 1: Data given

Volume of the closed flask = 200.00 mL = 0.2 L

Number of moles of CO = 2.000 mol

Number of moles of O2 = 2.000 mol

Temperature = 300.0 K

Pressure decreases with 10%

Step 2: The balanced equation

2CO(g)+O2(g)⟶2CO2(g)

Step 3: Calculate the initial pressure of the flask before the reaction

P = nRT/V

⇒ with n = the number of moles (2.000 moles CO + 2.000 moles O2 = 4.000 moles)

⇒ R is gas constant (0.08206 atm*L/mol*K)

⇒T = the temperature = 300.0K

⇒ V = the volume = 200.0 mL = 0.2 L

P = (4 * 0.08206*300)/0.2

P = 492.36 atm

Step 4: When the pressure is 10 % decreased:

The final pressure = 492.36 - 49.236 = 443.124 atm

Step 5: Calculate the number of moles

n = PV/RT

⇒ with n = the number of moles

⇒ with P = the pressure = 443.124 atm

⇒ V = the volume = 200.0 mL = 0.2 L

⇒ R is gas constant (0.08206 atm*L/mol*K)

⇒T = the temperature = 300.0K

n =(443.124*0.2)/(0.08206*300)

n = 3.6 moles = total number of moles

Step 6: Calculate number of moles

For the reaction :2CO(g) + O₂(g) ⟶ 2CO₂(g)

For each mole of O2 we have 2 moles of CO, to produce 2 moles of CO2

Moles CO = (2 -2X) moles

Moles O2 = (2-X) moles

Moles CO2 = 2X

The total number of moles (4 -X)= 3.6 moles

Where X are moles that react

X = 0.400 moles

There will react 0.400 moles of oxygen.

6 0

3 years ago

What occurs when Cr^3+ ions are reduced to Cr^2+ ions?

DiKsa [7]

D:

When electrons are gained, the charge of the atom decreases.

When you are given an atom with a charge, the oxidation of that atom is the charge. So by going from a Cr^3+ (Oxidation Number = 3) to a Cr^2+ (Oxidation Number = 2), the Oxidation Number thus decreases.

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3 years ago

A 5.024 mg sample of an unknown organic molecule containing carbon, hydrogen, and nitrogen only was burned and yielded 13.90 mg

Dafna1 [17]

Answer:

C8H17N

Explanation:

Mass of the unknown compound = 5.024 mg

Mass of CO2 = 13.90 mg

Mass of H2O = 6.048 mg

Next, we shall determine the mass of carbon, hydrogen and nitrogen present in the compound. This is illustrated below:

For carbon, C:

Molar mass of CO2 = 12 + (2x16) = 44g/mol

Mass of C = 12/44 x 13.90 = 3.791 mg

For hydrogen, H:

Molar mass of H2O = (2x1) + 16 = 18g/mol

Mass of H = 2/18 x 6.048 = 0.672 mg

For nitrogen, N:

Mass N = mass of unknown – (mass of C + mass of H)

Mass of N = 5.024 – (3.791 + 0.672)

Mass of N = 0.561 mg

Now, we can obtain the empirical formula for the compound as follow:

C = 3.791 mg

H = 0.672 mg

N = 0.561 mg

Divide each by their molar mass

C = 3.791 / 12 = 0.316

H = 0.672 / 1 = 0.672

N = 0.561 / 14 = 0.040

Divide by the smallest

C = 0.316 / 0.04 = 8

H = 0.672 / 0.04 = 17

N = 0.040 / 0.04 = 1

Therefore, the empirical formula for the compound is C8H17N

8 0

3 years ago