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3 years ago

Convert 2.57 x 10 10 atoms of Cr to moles

Chemistry

1 answer:

tatiyna3 years ago

6 0

Answer:

The mole is simply a very large number that is used by chemists as a unit of measurement.

Explanation:

The mole is thus the link between the micro world of atoms and molecules, and the macro world of grams and litres, the which we can easily measure by mass or volume. The masses for a mole of each element are given on the periodic table as the atomic weight. So, if have 12 g of

C , I know, fairly precisely, how many atoms of carbon I have. Given this quantity, I know how many molecules of O 2 are required to react with the C , which I could measure by mass or by volume.

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How many moles are in 2.4g of carbon dioxide (CO2)?

miv72 [106K]

Answer:

$\boxed {\boxed {\sf 0.055 \ mol \ CO_2}}$

Explanation:

To convert form grams to moles, the molar mass must be used. This is the mass (in grams) in 1 mole of a substance.

We can use the values on the Periodic Table. First, find the molar masses of the individual elements: carbon and oxygen.

C: 12.011 g/mol
O: 15.999 g/mol

Check for subscripts. The subscript of 2 after O means there are 2 oxygen atoms, so we have to multiply oxygen's molar mass by 2 before adding.

O₂: 2* (15.999 g/mol)=31.998 g/mol
CO₂: 12.011 g/mol + 31.998 g/mol =40.009 g/mol

Use the molar mass as a ratio.

$\frac {44.009 \ g\ CO_2}{ 1 \ mol \ CO_2}$

Multiply by the given number of grams.

$2.4 \ g \ CO_2 *\frac {44.009 \ g\ CO_2}{ 1 \ mol \ CO_2}$

Flip the fraction so the grams of carbon dioxide cancel.

$2.4 \ g \ CO_2 *\frac { 1 \ mol \ CO_2}{44.009 \ g\ CO_2}$

$2.4 *\frac { 1 \ mol \ CO_2}{44.009}$

$\frac { 2.4 \ mol \ CO_2}{44.009}= 0.0545342998 \ mol \ CO_2$

The original measurement of grams has 2 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place.

The ten thousandth place has a 5, so we round the 4 to a 5.

$0.055 \ mol \ CO_2$

2.4 grams of carbon dioxide is about 0.055 moles.

8 0

3 years ago

Which part of atom determine the identity of a atom

aksik [14]

Answer:

protons

Explanation:

the number of protons in 1 atom determine the identity

5 0

3 years ago

a chemist wants to combine carbon and iron to form steel. what type of bond will this chemist create between these two elements

iVinArrow [24]

I think its a covalent bond because carbon is positively charged and iron is positively charged too which makes the bond covalent. hope it helps

5 0

3 years ago

If the pH is 3.94 what is the concentration of H

solong [7]

Answer:

If pOH is 3.05, pH is 10.95 or

[H+]=1.122⋅10−11 mol/L

Explanation:

pH=−log(H+)Now, what is H+

if your pH is 10.95 (since pH+pOH=14, your pH=10.95).

(H+)=10 −10.95

(H+)=1.122⋅10 −11

This is your hydrogen ion concentration: [H+]=0.00000000001122 mol/L

7 0

3 years ago

____________ rays show areas where large quantities of energy are released.

sladkih [1.3K]

Answer:

Gamma

Explanation:

3 0

2 years ago