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4 years ago

How many atoms of chromium are in 0.86 mol of potassium chromate (K2CrO4)?

Chemistry

1 answer:

9966 [12]4 years ago

3 0

<h2>Answer:</h2>

Atoms of Cr in 0.86 mol of K2CrO4 = 0.86 × 6.02*10^23 = 5.177 * 10^23 atoms.

<h3>Explanation:</h3>

One mol of K2CrO4 contains 6.02*10^23 molecules of K2CrO4.
One K2CrO4 contains 1 atom of Cr.
So 0.86 mol of K2CrO4 contain 0.86 * 6.02*10^23.
Which is equal to 5.177 * 10^23 atoms.

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What happens to the number of neutrons as you move across the table? left to right

luda_lava [24]

Answer: The number of neutrons will increase as we move from left to right in a periodic table.

Explanation:

Atomic number is equal to the number of protons.

Mass number is the sum of number of neutrons and number of protons.

As we move from left to right, both the atomic number and mass number increases.

For example: As we move from Lithium to berrylium to boron to carbon to nitrogen to oxygen to fluorine to neon , the number of neutrons increase from 4 to 5 to 6 to 6 to 7 to 8 to 10 to 10.

Thus the number of neutrons will also increase as we move from left to right in a periodic table.

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2 years ago

PLEAS HELP ASAP!!! Which of these statements best explains why the running costs for geothermal power plants are very low?

natima [27]

Correct answer is Fuels do not have to be purchased to generate power.

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3 years ago

PLEASE HELP ME I NEED HELP

Crazy boy [7]

Answer:

5 moles S x (36.02 g S/mole S) = 180.1 grams of S

Explanation:

The periodic table has mass units for every element that can be correlated with the number of atoms of that element. The relationship is known as Avogadro's Number. This number, 6.02x $10^{23}$ , is nicknamed the mole, which scientists found to be a lot more catchy, and easier to write than 6.02x $10^{23}$ . The mole is correlated to the atomic mass of that element. The atomic mass of sulfur, S, is 36.02 AMU, atomic mass units. But it can also be read as 36.02 grams/mole.

This means that 36.02 grams of S contains 1 mole (6.02x $10^{23}$ ) of S atoms.

This relationship holds for all the elements. Zinc, Zn, has an atomic mass of 65.38 AMU, so it has a "molar mass" of 65.38 grams/mole. ^5.38 grams of Zn contains 1 mole of Zn atoms.

And so on.

5.0 moles of Sulfur would therefore contain:

(5.0 moles S)*(36.02 grams/mole S) = 180.1 grams of S

Note how the units cancel to leaves just grams. The units are extremely helpful in mole calculations to insure the correct mathematical operation is done. To find the number of moles in 70 g of S, for example, we would write:

(70g S)/(36.02 grams S/mole S) = 1.94 moles of S. [Note how the units cancel to leave just moles]

4 0

2 years ago

Identify the only polyatomic ion below that is NOT an oxyanion. Your answer: A Cyanide B Nitrate C Hydroxide D Sulfate

DochEvi [55]

Answer:

Cyanide

Explanation:

Molecular Structure of Each Answer

A: CN-

B: NO3-

C: OH-

D: SO4 2-

As you can see, only A (Cyanide) is the only compound that does not contain oxygen, meaning it is NOT an oxyanion.

7 0

3 years ago

Before we can use this equation for

AlexFokin [52]

Answer:

2C₂H₆ + [7]O₂ → [4]CO₂ + [6]H₂O

Explanation:

Chemical equation:

C₂H₆ + O₂ → CO₂ + H₂O

Balanced chemical equation:

2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

Step 1:

2C₂H₆ + O₂ → CO₂ + H₂O

Left hand side Right hand side

C = 4 C = 1

H = 12 H = 2

O = 2 O = 3

Step 2:

2C₂H₆ + O₂ → 4CO₂ + H₂O

Left hand side Right hand side

C = 4 C = 4

H = 12 H = 2

O = 2 O = 9

Step 3:

2C₂H₆ + O₂ → 4CO₂ + 6H₂O

Left hand side Right hand side

C = 4 C = 4

H = 12 H = 12

O = 2 O = 14

Step 4:

2C₂H₆ + 7O₂ → 4CO₂ + 6H₂O

Left hand side Right hand side

C = 4 C = 4

H = 12 H = 12

O = 14 O = 14

3 0

3 years ago