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3 years ago

How many atoms are in a sample of carbon weighing 16 grams? Round your answer to two decimal places.

Chemistry

1 answer:

Gennadij [26K]3 years ago

8 0

Answer:

d) 8.01 E23 atoms

Explanation:

mol ≡ 6.022 E23 atoms

∴ mass C = 16 g

∴ molar mass C = 12.0107 g/mol

⇒ mol C = (16 g)*(mol/12.0107 g) = 1.332 mol

⇒ atoms C = (1.332 mol)*(6.022 E23 atoms/mol)

⇒ atoms C = 8.02 E23 atoms

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Potassium chlorate is a white, crystalline solid. It can be broken down into potassium chloride (a salt)

lions [1.4K]

Answer:

Notice that the number of atoms of

and

are the same on both sides, but the numbers of

atoms are not. There are 3

atoms on the the left side and 2 on the right. 3 and 2 are factors of 6, so add coefficients so that there are 6

atoms on both sides.

2KClO

(

)

+ heat

→

KCl(s)

(

)

Now the

and

atoms are not balanced. There are 2 of each on the left and 1 of each on the right. Add a coefficient of 2 in front of

KCl

2KClO

(

)

+ heat

→

2KCl(s)

(

)

The equation is now balanced with 2

atoms,

7 0

3 years ago

Read 2 more answers

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

Here is the electron configuration for Magnesium. How many total electrons are in the 2nd energy level?

balandron [24]

Answer:

8 electrons

Explanation:

Magnesium is present on group 2.

It has 2 valence electrons.

Electronic configuration of magnesium:

Mg₁₂ = 1s² 2s² 2p⁶ 3s²

1st energy level contain 2 electrons.(1s²)

2nd energy level contain 8 electrons. (2s² 2p⁶)

3rd energy level contain 2 electrons. (3s²)

3rs energy level of magnesium is called valence shell. It contain two valance electrons. Magnesium can easily donate its two valance electrons and get stable electronic configuration.

It react with halogens and form salt. For example,

Mg + Cl₂ → MgCl₂

7 0

3 years ago

Why is ginger used in food preservation

Vaselesa [24]

Spices like ginger are significantly used in preservatives because they have antimicrobial properties in their chemical compounds. They also have antioxidant properties that allow food to be preserved.

6 0

3 years ago

Which of the following units is used to measure force ?

Sati [7]

C.) Newton. & it's S.I. Unit of Force.

Hope this helps!

3 0

3 years ago

Read 2 more answers