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3 years ago

When did oxygen first appear in earth's atmosphere??

1 answer:

7 0

<span> the atmosphere holds about 21 per cent oxygen. Over the Earth’s 4.6 billion year history, oxygen did not appear in the atmosphere until perhaps about 2.5 billion years ago. Since then, oxygen levels have fluctuated in tandem with global geological and biological events, such as mass extinctions.</span>

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3. What is the easiest way to create electron configurations?

jarptica [38.1K]

Answer:

To calculate an electron configuration, divide the periodic table into sections to represent the atomic orbitals, the regions where electrons are contained. Groups one and two are the s-block, three through 12 represent the d-block, 13 to 18 are the p-block and the two rows at the bottom are the f-block.Explanation:

6 0

2 years ago

Suppose 110.0 mL110.0 mL of hydrogen gas at STP combines with a stoichiometric amount of fluorine gas and the resulting hydrogen

Fittoniya [83]

Suppose 110.0 mL of hydrogen gas at STP combines with a stoichiometric amount of fluorine gas and the resulting hydrogen fluoride dissolves in water to form 150.0 mL of an aqueous solution. 0.032 M is the concentration of the resulting hydrofluoric acid.

<h3>What is Balanced Chemical Equation ?</h3>

The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.

Now write the balanced chemical equation

H₂ + F₂ → 2HF

<h3>What is Ideal Gas ?</h3>

An ideal gas is a gas that obey gas laws at all temperature and pressure conditions. It have velocity and mass but do not have volume. Ideal gas is also called perfect gas. Ideal gas is a hypothetical gas.

It is expressed as:

PV = nRT

where,

P = Pressure

V = Volume

n = number of moles

R = Ideal gas constant

T = temperature

Here,

P = 1 atm [At STP]

V = 110 ml = 0.11 L

T = 273 K [At STP]

R = 0.0821 [Ideal gas constant]

Now put the values in above expression

PV = nRT

1 atm × 0.11 L = n × 0.0821 L.atm/ K. mol × 273 K

$n = \frac{1\ \text{atm} \times 0.11\ L}{0.0821\ \text{L. atm/ K. mol} \times 273\ K}$

n = 0.0049 mol

<h3>How to find the concentration of resulting solution ? </h3>

To calculate the concentration of resulting solution use the expression

$C = \frac{n}{V}$

$= \frac{0.0049}{0.15}$

= 0.032 M

Thus from the above conclusion we can say that Suppose 110.0 mL of hydrogen gas at STP combines with a stoichiometric amount of fluorine gas and the resulting hydrogen fluoride dissolves in water to form 150.0 mL of an aqueous solution. 0.032 M is the concentration of the resulting hydrofluoric acid.

Learn more about the Ideal Gas here: brainly.com/question/25290815
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4 0

2 years ago

(Science)<br> why is the 10g of shampoo is more dense than the 10kg of the same shampoo?

igor_vitrenko [27]

Grams (g) is much lighter than kilograms (kg)

6 0

2 years ago

When does the shape of a molecule affect its polarity?

Aliun [14]

Answer:

I think no C