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3 years ago

How many atoms are in 2.70 moles of iron (Fe) atoms?

Chemistry

1 answer:

vredina [299]3 years ago

3 0

The answer is 1.63 × 1024 atoms Fe.

Avogadro's number is the number of units (atoms, molecules) in 1 mole of substance:

6.023 × 10²³ atoms per 1 mole
So, how many atoms are per 2.70 moles:

6.023 × 10²³ atoms : 1 mole = x : 2.70 moles
x = 6.023 × 10²³ atoms * 2.70 moles : 1 mole
x = 16.3 × 10²³ = 1.63 × 10 × 10²³ = 1.63 × 10²⁴ atoms

You might be interested in

Which shows the rational expression written using the least common denominator?

Alexandra [31]

Answer:

The first one.

$\frac{x + 1}{4x^{2} } and \frac{4(x + 1)}{4x^{2} }$

Explanation:

When comparing two fractions with variables like this, it's important to get to the same denominator in order to compare apples with apples and then be able to do not only comparisons but also perform additions/subtractions.

Question is which denominator to use and how to reach it.

In this case, the question and the answer choices do the work for you. The question asks which one is the LEAST common denominator, and the answers show denominators x² and 4x². The smallest of these is x², however, we can't simplify the first fraction to get to the x² denominator, so we'll go for the 4x².

So, the first fraction has already the correct denominator (4x²), we just have to transform the second one.

We multiply it by 1, expressed in a different way. Since we're multiplying by one, we're not affecting the value, just the way it looks.

Let's do it!, to get the denominator to go from x² to 4x², we need to multiply it by 4... so we'll multiply by 4/4 (which is 1, neutral for the multiplication).

$\frac{x + 1}{x^{2} } * \frac{4}{4} = \frac{4(x + 1)}{4x^{2} }$

And now you have both fractions on the same denominator, without having changed their value, just their looks

6 0

3 years ago

Which best describes the importance of the microscope to the development of cell theory? Microscopes color different parts of ce

aliya0001 [1]

Cells are too small to see with the naked eye.

It's pretty straight forward, use the cross-out method.

1) Microscopes MAGNIFY images, they don't color the cells. In fact, scientists have to use these chemicals to "stain" or color the cells to see them more easily through microscopes.

2) If the lenses of a microscope reduced the image of an organism to the size of a cell, you'd be seeing a very tiny human through your microscope, instead of actual cells.

3) Microscopes don't "trap" anything. In fact, scientists use plates or slides under microscopes to contain what they're studying.

8 0

3 years ago

Read 2 more answers

Conserving water can save money while protecting the environment. True or False

blagie [28]

Answer: The given statement is true.

Explanation:

Water is a natural resource present in the nature and it is very precious as life without it is impossible.

So, when we unnecessarily use water then it means we are wasting a natural resource that cannot be reproduced again by human beings.

Therefore, more we are able to conserve water more we can protect other human life's and environment also.

If there is shortage of water then its prices will go high and hence we need to pay more for it.

Thus, we can conclude that the statement conserving water can save money while protecting the environment, is true.

3 0

3 years ago

Read 2 more answers

4. A balloon is filled with 3.0 L of helium at 310 K. The balloon is placed in an oven where the

77julia77 [94]

Answer:

3,29L

Explanation:

3.29L = V2

Formula: V1/T1 = V2/T2

--------------------

Given:

V1 = 3.0 L V2 = ?

T1 = 310 K T2 = 340 K

--------------------

Plugin:

(X stands in place of V2 just to make it easier to look at)

[3.0L / 310K = X / 340K]

(3.0L / 310K = 0.01L/K)

0.01L/K = X / 340K

(multiply 340K on both sides, it cancels out on the right)

0.01L/K * 340K = X

(0.01L/K * 340K = 3.29L)

**3.29L = X**

[or]

**3.29L = V2**

4 0

3 years ago

Combustion analysis of a 13.42-g sample of the unknown organic compound (which contains only carbon, hydrogen, and oxygen) produ

kirza4 [7]

Answer: The molecular formula for the given organic compound is $C_{18}H_{20}O_2$

Explanation:

The chemical equation for the combustion of hydrocarbon having carbon, hydrogen and oxygen follows:

$C_xH_yO_z+O_2\rightarrow CO_2+H_2O$

where, 'x', 'y' and 'z' are the subscripts of Carbon, hydrogen and oxygen respectively.

We are given:

Mass of $CO_2=39.61g$

Mass of $H_2O=9.01g$

We know that:

Molar mass of carbon dioxide = 44 g/mol

Molar mass of water = 18 g/mol

For calculating the mass of carbon:

In 44 g of carbon dioxide, 12 g of carbon is contained.

So, in 39.61 g of carbon dioxide, $\frac{12}{44}\times 39.61=10.80g$ of carbon will be contained.

For calculating the mass of hydrogen:

In 18 g of water, 2 g of hydrogen is contained.

So, in 9.01 g of water, $\frac{2}{18}\times 9.01=1.00g$ of hydrogen will be contained.

Mass of oxygen in the compound = (13.42) - (10.80 + 1.00) = 1.62 g

To formulate the empirical formula, we need to follow some steps:

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{10.80g}{12g/mole}=0.9moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{1g}{1g/mole}=1moles$

Moles of Oxygen = $\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{1.62g}{16g/mole}=0.10moles$

Step 2: Calculating the mole ratio of the given elements.

For the mole ratio, we divide each value of the moles by the smallest number of moles calculated which is 0.10 moles.

For Carbon = $\frac{0.9}{0.10}=9$

For Hydrogen = $\frac{1}{0.10}=10$

For Oxygen = $\frac{0.10}{0.10}=1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : O = 9 : 10 : 1

Hence, the empirical formula for the given compound is $C_9H_{10}O$

For determining the molecular formula, we need to determine the valency which is multiplied by each element to get the molecular formula.

The equation used to calculate the valency is :

$n=\frac{\text{Molecular mass}}{\text{Empirical mass}}$

We are given:

Mass of molecular formula = 268.34 g/mol

Mass of empirical formula = 134 g/mol

Putting values in above equation, we get:

$n=\frac{268.34g/mol}{134g/mol}=2$

Multiplying this valency by the subscript of every element of empirical formula, we get:

$C_{(9\times 2)}H_{(10\times 2)}O_{(1\times 2)}=C_{18}H_{20}O_2$

Thus, the molecular formula for the given organic compound is $C_{18}H_{20}O_2$ .

3 0

3 years ago