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2 years ago

How many atoms are in 80.45 g of magnesium?

Chemistry

1 answer:

KatRina [158]2 years ago

8 0

Hello!

To find the amount of atoms that are in 80.45 grams of magnesium, we will need to know Avogadro's number and the mass of one mole of magnesium.

Avogadro's number is 6.02 x 10^23 atoms, and one mole of magnesium is equal to 24.31 grams.

1. Divide by one mole of magnesium

80.45 / 24.31 = 3.309 moles (rounded to the number of sigfigs)

2. Multiply moles by Avogadro's number

3.309 x (6.02 x 10^23) = 1.99 x 10^24 (rounded to the number of sigfigs)

Therefore, there are 1.99 x 10^24 atoms in 80.45 grams of magnesium.

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Magnesium reacts with a certain element to form a compound with the general formula MgX. What would the most likely formula be f

Rama09 [41]

Answer:

K2X

Explanation:

Valency can be defined as the combining power of an element. It is the valency that dictates the value an element will have when writing a chemical formula for its compound.

MgX is a compound of magnesium and an element X. The valency of magnesium in most of its compound is +2. Now for the 2 to have been absent in the chemical formula, this shows that the element X itself have a valency if -2 for the valencies of both to have canceled out.

Now considering the element potassium, it is an alkaline metal belonging to group 1 of the periodic table. Hence, it is expected that it has a valency of +1

Forming a compound with element X means there would be an exchange of valencies between the two. We have established that x has a valency of -2. The formula of the compound thus formed by exchanging the valencies of both element would be K2X

4 0

2 years ago

Why does 5060 have three significant figures?

Morgarella [4.7K]

<h2>5060 have three significant figures : Explanation given below </h2>

Explanation:

Significant figures

The significant figures (also known as the significant digits and decimal places) of a number are digits that possess certain meaning .

It includes all digits except: zeros

Rules to find significant figures

1.All non-zero digits are considered significant. For example, 23 has two significant figures.

2.Zeros in between two non-zero digits are significant: like in 202.1201 has seven significant figures.

3.Zeros to the left of the significant figures are not significant. For example, .000021 has two significant figures, zeros have no value .

4.Zeros to the right of the significant figures are significant.

That is the reason in number 5060 , it has 3 significant figures .

3 0

2 years ago

A 23.2 g sample of an organic compound containing carbon, hydrogen and oxygen was burned in excess oxygen and yielded 52.8 g of

allochka39001 [22]

Answer:

The answer to your question is C₃H₆O

Explanation:

Data

mass of sample = 23.2 g

mass of carbon dioxide = 52.8 g

mass of water = 21.6 g

empirical formula = ?

Process

1.- Calculate the mass and moles of carbon

44 g of CO₂ --------------- 12 g of C

52.8 g --------------- x

x = (52.8 x 12)/44

x = 633.6/44

x = 14.4 g of C

12 g of C ------------------ 1 mol

14.4 g of C --------------- x

x = (14.4 x 1)/(12)

x = 1.2 moles of C

2.- Calculate the grams and moles of Hydrogen

18 g of H₂O --------------- 2 g of H

21.6 g of H₂O ------------- x

x = (21.6 x 2) / 18

x = 2.4 g of H

1 g of H -------------------- 1 mol of H

2.4 g of H ----------------- x

x = (2.4 x 1)/1

x = 2.4 moles of H

3.- Calculate the grams and moles of Oxygen

Mass of Oxygen = 23.2 - 14.4 - 2.4

= 6.4 g

16 g of O ---------------- 1 mol

6.4 g of O -------------- x

x = (6.4 x 1)/16

x = 0.4 moles of Oxygen

4.- Divide by the lowest number of moles

Carbon = 1.2 / 0.4 = 3

Hydrogen = 2.4/ 0.4 = 6

Oxygen = 0.4 / 0.4 = 1

5.- Write the empirical formula

C₃H₆O

8 0

2 years ago

Alveolar air (a mixture of nitrogen, oxygen, and carbon dioxide) has a total pressure of 0.998 atm. If the partial pressure of o

inn [45]

Answer:

The partial pressure of carbon dioxide is 22.8 mmHg

Explanation:

Dalton's Law is a gas law that relates the partial pressures of the gases in a mixture. This law says that the pressure of a gas mixture is equal to the sum of the partial pressures of all the gases present.

In this case:

Ptotal=Pnitrogen + Poxygen + Pcarbondioxide

You know that:

Ptotal= 0.998 atm
Pnitrogen= 0.770 atm
Poxygen= 0.198 atm
Pcarbondioxide= ?

Replacing:

0.998 atm=0.770 atm + 0.198 atm + Pcarbondioxide

Solving:

Pcarbondioxide= 0.998 atm - 0.770 atm - 0.198 atm

Pcarbondioxide= 0.03 atm

Now you apply the following rule of three: if 1 atm equals 760 mmHg, 0.03 atm how many mmHg equals?

$Pcarbondioxide=\frac{0.03 atm*760 mmHg}{1 atm}$

Pcarbondioxide= 22.8 mmHg

<u><em>The partial pressure of carbon dioxide is 22.8 mmHg</em></u>

6 0

2 years ago

Write the Lewis structure for ethanol (CH3CH2OH), the alcohol found in alcoholic beverages, then answer the following questions:

hodyreva [135]

Answer :

(1) The number of valence electrons present in the compound is, 20

(2) The number of bonded electrons present in the compound is, 16

(3) The number of lone pair electrons present in the compound is, 4

(4) The number of single bonds present in the compound is, 8

Explanation :

Lewis-dot structure : It shows the bonding between the atoms of a molecule and it also shows the unpaired electrons present in the molecule.

In the Lewis-dot structure the valance electrons are shown by 'dot'.

The given molecule is, $CH_3CH_2OH$

As we know that carbon has '4' valence electrons, hydrogen has '1' valence electrons and oxygen has '6' valence electrons.

Therefore, the total number of valence electrons in $CH_3CH_2OH$ = 2(4) + 6(1) + 6 = 20

According to Lewis-dot structure, there are 16 number of bonding electrons and 4 number of non-bonding electrons or lone pair of electrons.

The Lewis-dot structure of $CH_3CH_2OH$ is shown below.

8 0

2 years ago