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3 years ago

Select all that apply.

Chemistry

2 answers:

DIA [1.3K]3 years ago

7 0

Explanation:

Ground water is defined as the water present below the ground. When chemicals spill from factories, industries etc then they are absorbed by soil from where it flows through the pores present in it.

Pesticides and fertilizers also contain toxic substances which flow and absorbed by the ground when it rains.

Hence, they also contribute to water pollution.

Thus, we can conclude that ground water pollution can be caused by chemical spills, pesticides and fertilizers.

Vesna [10]3 years ago

3 0

Select them all.
It's All of the above.

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Would you be able to fit a mole of rice in a 30.0m*8.5m*3.5m room??

Julli [10]

Answer:

No.

Explanation:

1. Volume of a rice grain

There is no standard for the size of a rice grain, so let's make an arbitrary assumption.

An average rice grain behaves as if it were a rectangular solid with dimensions 7 mm × 2 mm × 2 mm.

The volume of one rice grain is

V = lwh = 7 mm × 2 mm × 2 mm = 28 mm³

Convert to cubic metres :

$V = \text{28 mm}^{3} \times \left (\dfrac{\text{1 m}}{\text{1000 mm}}\right )^{3} = \mathbf{2.8 \times 10^{-8}}\textbf{ m}^{\mathbf{3}}$

2. Volume of the room

V = lwh = 30.0 m × 8.5 m × 3.5 m = 890 m³

3. Volume of a mole of rice

$V= 6.022 \times 10^{23}\text{ grains} \times \dfrac{2.8 \times 10^{-8}\text{ m}^{3}}{\text{1 grain }} = \mathbf{1.7 \times 10^{16}}\textbf{ m}^{\mathbf{3}}$

4. Conclusion

The room is not big enough to hold a mole of rice.

If you work it out, you will find that it takes about

20 000 000 000 000 (twenty trillion) rooms to hold a mole of rice.

8 0

3 years ago

Adipic acid, C6H10O4, is a raw material for the making of nylon and it can be prepared in the laboratory by the following reacti

Dafna1 [17]

Mass of Cyclohexen : 10.2 g

<h3>Further explanation</h3>

Reaction

3 C6H10 + 4 Na2Cr2O7 + 16 H2SO4 >

3 C6H10O4 + 4 Cr2(SO4)3 + 4Na2SO4 + 16 H2O

mol C6H10 : mol C6H10O4 = 3 : 3 = 1 : 1

$\tt \%yield=\dfrac{actual}{theoretical}\times 100\%\\\\68.6\%=\dfrac{12.5}{theoretical}\times 100\%\\\\theoretical=18.22~g$

12.5 grams of C6H10O4 , mol C6H10O4 (MW 146.14 g/mol):

$\tt \dfrac{18.22}{148}=0.123$

mol C6H10 = mol C6H10O4 = 0.124

mass C6H10 :

$\tt 0.124\times 82.16=10.2~g$

6 0

2 years ago

A student was given a 50.0 mL of 0.10 M solution of an unknown diprotic acid, H2A, which was titrated with 0.10 M NaOH. After a

stich3 [128]

Answer:

Ka1 = 2.00x10⁻⁷, Ka2 = 5.00x10⁻¹⁰

Explanation:

A diprotic acid is a substance that can release 2 H⁺ when in aqueous solution. Because it is a weak acid, the ionization will be reversible. So, the acid has two equilibrium reactions, each one with its equilibrium constant:

H₂A ⇄ H⁺ + HA⁻ Ka1 = ([HA⁻]*[H⁺]/[H₂A])

HA⁻ ⇄ H⁺ + A⁻ Ka2 = ([A⁻]*[H⁺]/[HA⁻])

First, the number of moles of H₂A was:

n = 0.10 mol/L *0.05L = 0.005 mol

And then was added NaOH:

n = 0.1 mol/L * 0.025 L = 0.0025 mol

So, all the NaOH will reacts, then, the number of moles will be:

H₂A = 0.005 - 0.0025 = 0.0025 mol

HA⁻ = 0.0025 mol (the stoichiometry is 1:1:1)

The concentrations of H₂A and HA⁻ will be the same, so Ka1 = [H⁺], and

pH = -log[H⁺]

6.70 = -log[H⁺]

[H⁺] = $10^{-6.70}$

[H⁺] = 2.00x10⁻⁷ M

Ka1 = 2.00x10⁻⁷

After the addition of 50.0 mL of NaOH the second equilibrium must dominate the reaction. For the expression of Ka1:

Ka1 = ([HA⁻]*[H⁺]/[H₂A])

[HA⁻]*[H⁺] = Ka1*[H₂A]

[HA⁻] = (Ka1*[H₂A])/[H⁺]

Ka2 = ([A⁻]*[H⁺]/[HA⁻])

Ka2 = ([A⁻]*[H⁺]²)/(Ka1*[H₂A])

By the stoichiometry, [H₂A] = [A⁻], so:

Ka2 = [H⁺]²/Ka1

pH = -log[H⁺]

8.00 = -log[H⁺]

[H+] = 10⁻⁸

Ka2 = (10⁻⁸)²/(2.00x10⁻⁷)

Ka2 = 5.00x10⁻¹⁰

4 0

3 years ago

It is obvious that the large stalactites in an underground cavern must have required long ages to form. True False

aivan3 [116]

True, it is formed from immense weathering over time. Hope it helped!

6 0

3 years ago

Which of the following is a chemical property of water?

RoseWind [281]

Its D as A, B and C are physical properties of water

3 0

3 years ago