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3 years ago

Which statement correctly describes a physical change?

Chemistry

1 answer:

MArishka [77]3 years ago

4 0

Answer: Option (b) is the correct answer.

Explanation:

A change which brings no change in chemical composition of a substance is known as a physical change.

For example, melting of ice is a physical change as there occurs change in phase from solid state to liquid state of water. Whereas the structure of water remains the same.

Therefore, we can conclude that the statement which describes a physical change is that it may involve a change in phase but does not involve a change in the molecular structure.

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What is the electron configuration for<br> 08<br> 16

Elis [28]

The electron configuration for Oxygen : [He] 2s²2p⁴

<h3>Further explanation</h3>

Writing electron configurations starts from the lowest to the highest sub-shell energy level. There are 4 sub-shells in the shell of an atom, namely s, p, d, and f. The maximum number of electrons for each sub-shell is

• s: 2 electrons

• p: 6 electrons

• d: 10 electrons and

• f: 14 electrons

Charging electrons in the sub-shell uses the following sequence:

The element is Oxgen, with symbol O, and :

the atomic number=8=number of electron

the atomic mass=16

The electron configuration based on the number of electrons(for Oxygen=8), so the configuration :

$\tt _8^{16}O:1s^22s^22p^4$ or we can write with noble gas [He] 2s²2p⁴

3 0

2 years ago

The combustion of 0.570 g of benzoic acid (ΔHcomb = 3,228 kJ/mol; MW = 122.12 g/mol) in a bomb calorimeter increased the tempera

torisob [31]

Answer:

The temperature change from the combustion of the glucose is 6.097°C.

Explanation:

Benzoic acid;

Enthaply of combustion of benzoic acid = 3,228 kJ/mol

Mass of benzoic acid = 0.570 g

Moles of benzoic acid = $\frac{0.570 g}{122.12 g/mol}=0.004667 mol$

Energy released by 0.004667 moles of benzoic acid on combustion:

$Q=3,228 kJ/mol \times 0.004667 mol=15.0668 kJ=15,066.8 J$

Heat capacity of the calorimeter = C

Change in temperature of the calorimeter = ΔT = 2.053°C

$Q=C\times \Delta T$

$15,066.8 J=C\times 2.053^oC$

$C=7,338.92 J/^oC$

Glucose:

Enthaply of combustion of glucose= 2,780 kJ/mol.

Mass of glucose=2.900 g

Moles of glucose = $\frac{2.900 g}{180.16 g/mol}=0.016097 mol$

Energy released by the 0.016097 moles of calorimeter combustion:

$Q'=2,780 kJ/mol \times 0.016097 mol=44.7491 kJ=44,749.1 J$

Heat capacity of the calorimeter = C (calculated above)

Change in temperature of the calorimeter on combustion of glucose = ΔT'

$Q'=C\times \Delta T'$

$44,749.1 J=7,338.92 J/^oC\times \Delta T'$

$\Delta T'=6.097^oC$

The temperature change from the combustion of the glucose is 6.097°C.

6 0

3 years ago

Which statement describes climate and not weather?

sasho [114]

I would answer B!! But your guess is as good as mine!!

3 0

3 years ago

Read 2 more answers

9. In a sample of gas, what causes pressure? Answer in a completesentence.

hammer [34]

Answer:

physical properties of gases, that is, pressure, volume, temperature, and amount of gas

7 0

3 years ago

Ethane, C2H6, burns in oxygen. First write a balanced equation for this combustion reaction. What mass of oxygen, in grams, is r

iren [92.7K]

Answer:

We need 50.6 grams of oxygen

Explanation:

Step 1: Data given

Mass of ethane = 13.6 grams

Molar mass of ethane = 30.07 g/mol

Step 2: The balanced equation

2C2H6 + 7O2 → 4CO2 + 6H2O

Step 3: Calculate moles ethane

Moles ethane = mass ethane / molar mass ethane

Moles ethane = 13.6 grams / 30.07 g/mol

Moles ethane = 0.452 moles

Step 4: Calculate moles oxygen

For 2 moles ethane we need 7 moles O2 to produce 4 moles CO2 and 6 moles H2O

For 0.452 moles ethane we need 3.5*0.452 = 1.582 moles O2

Step 5: Calculate mass O2

Mass O2 = moles O2 * molar mass O2

Mass O2 = 1.582 moles * 32.0 g/mol

Mass O2 = 50.6 grams

We need 50.6 grams of oxygen

7 0

3 years ago