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2 years ago

Question 1 of 7

Chemistry

2 answers:

Nata [24]2 years ago

8 0

Answer:

Explanation:

nlexa [21]2 years ago

3 0

Answer:

Explanation:B ice melting is a phiyscal change and the mass of the substance remains the same

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P l e a s e help me omg I'm so confused-I'll give 40 points, I only have 45-

stiks02 [169]

M is not as thick as N, It only takes 100°C to boil water whereas it takes 300°C to boil soybean oil

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3 years ago

What is the percent composition of silicon dioxide, SiO2 ? (Atomic masses : O = 16 . 0 Si =28 .1

weeeeeb [17]

Answer:

60.1 i think

Explanation:

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3 years ago

Suppose a group of volunteers is planning to build a park near a local lake. The lake is known to contain low levels of arsenic

Kisachek [45]

Answer:

A) 10.75 is the concentration of arsenic in the sample in parts per billion .

B) 7,633.66 kg the total mass of arsenic in the lake that the company have to remove.

C) It will take 1.37 years to remove all of the arsenic from the lake.

Explanation:

A) Mass of arsenic in lake water sample = 164.5 ng

The ppb is the amount of solute (in micrograms) present in kilogram of a solvent. It is also known as parts-per million.

To calculate the ppm of oxygen in sea water, we use the equation:

$\text{ppb}=\frac{\text{Mass of solute}}{\text{Mass of solution}}\times 10^9$

Both the masses are in grams.

We are given:

Mass of arsenic = 164.5 ng = $164.5\times 10^{-9} g$

$1 ng=10^{-9} g$

Volume of the sample = V = $15.3 cm^3$

Density of the lake water sample ,d= $1.00 g/cm^3$

Mass of sample = M = $d\times V=1.0 g/cm^3\times 15.3 cm^3=15.3 g$

$ppb=\frac{164.5\times 10^{-9} g}{15.3 g}\times 10^9=10.75$

10.75 is the concentration of arsenic in the sample in parts per billion.

Mass of arsenic in $1 cm^3$ of lake water = $\frac{164.5\times 10^{-9} g}{15.3}=1.075\times 10^{-8} g$

Mass of arsenic in $0.710 km^3$ lake water be m.

$1 km^3=10^{15} cm^3$

Mass of arsenic in $0.710\times 10^{15} cm^3$ lake water :

$m=0.710\times 10^{15}\times 1.075\times 10^{-8} g=7,633,660.130 g$

1 g = 0.001 kg

7,633,660.130 g = 7,633,660.130 × 0.001 kg=7,633.660130 kg ≈ 7,633.66 kg

7,633.66 kg the total mass of arsenic in the lake that the company have to remove.

Company claims that it takes 2.74 days to remove 41.90 kilogram of arsenic from lake water.

Days required to remove 1 kilogram of arsenic from the lake water :

$\frac{2.74}{41.90} days$

Then days required to remove 7,633.66 kg of arsenic from the lake water :

$=7,633.66\times \frac{2.74}{41.90} days=499.19 days$

1 year = 365 days

499.19 days = $\frac{499.19}{365} years = 1.367 years\approx 1.37 years$

It will take 1.37 years to remove all of the arsenic from the lake.

3 0

3 years ago

If a reaction ends with 5.5 grams of products, how many grams of reactants were required to start the reaction?

xz_007 [3.2K]

5.5 grams of reactants. According to the Law of Conservation of Mass, mass isn’t created or lost through any chemical changes, so the total mass should remain constant from the initial reactants to the final products.

5 0

3 years ago

Do light waves interact with all mediums the same?

jeka94

Answer:

Light can be reflected, transmitted, or absorbed. You have read that EM waves can interact with a material medium in the same ways that mechanical waves do.

Explanation:

7 0

3 years ago

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