Chemistry, 26.01.2020 16:31 jaymee2904p88tgh

You perform a combustion analysis on a 255 mg sample of a substance that contains only c, h, and o, and you find that 561 mg of co2 is produced, along with 306 mm of h2o.

if the substance contains only c, h, and o, what is the empirical formula
if the molar mass of the compound is 180 g/mol what is the molecular formula of the compound

Answers: 1

Show answers

Answers

The combustion of an organic compound is mostly written as,
CaHbOc + O2 --> CO2 + H2O
where a, b, and c are supposed to be the subscripts of the elements C, H, and O in the compound. Determining the number of moles of C and H in the product which is the same as that in the compound,
(Carbon, C) : (561 mg) x (12/44) = 153 mg x (1 mmole/12 mg) = 12.75
(Hydrogen, H) : (306 mg) x (2/18) = 34 mg x (1 mmole/1 mg) = 34
Calculating for amount of O in the sample,
(oxygen, O) = 255 - 153 mg - 34 mg = 68 mg x (1mmole/16 mg) = 4.25
The empirical formula is therefore,
C(51/4)H34O17/4
C3H8O1
The molar mass of the empirical formula is 60. Therefore, the molecular formula of the compound is,
C9H24O3

Answer from: alisonlebron15

molecular formula of compound =C₉H₂₄O₃

Explanation:

The compound contains only C,H and O

The combustion equation for carbon is:

$C+O_{2}--CO_{2}$

Thus if we are obtaining 44g of carbon dioxide it means the amount of carbon is 12g.

If we are getting 1g of carbon dioxide, it means the amount of carbon = $\frac{12}{44}g$

If we are getting 561mg of carbon dioxide, it means the amount of carbon= $\frac{12X561}{44}=153mg$

So the mass of carbon in the given sample = 153mg

Percentage of carbon = $\frac{massofcarbonX100}{massofsample}=\frac{153X100}{255}=60$

The combustion equation for hydrogen is:

$H_{2}+0.5O_{2}--H_{2}O$

Thus if we are obtaining 18g of water it means the amount of hydrogen is 2g.

If we are getting 1g of water, it means the amount of hydrogen = $\frac{2}{18}g$

If we are getting 306mg of water, it means the amount of hydrogen= $\frac{2X306}{18}=34mg$

So the mass of hydrogen in the given sample = 34mg

Percentage of hydrogen = $\frac{massofhydrogenX100}{massofsample}=\frac{34X100}{255}=13.33$

Percentage of oxygen=100-(60+13.33)=26.67%

The moles of each element in 100g of sample will be

moles of carbon = $\frac{mass}{atomicmass}=\frac{60}{12}=5$

moles of hydrogen = $\frac{mass}{atomicmass}=\frac{13.33}{1}=13.33$

moles of oxygen = $\frac{mass}{atomicmass}=\frac{26.67}{16}=1.67$

Let us divide all the moles with 1.67

moles of carbon = 3

moles of hydrogen = 8

moles of oxygen = 1

So the empirical formula of the compound would be:C₃H₈O

The empirical mass = 60

molar mass = 180g

So the molecular formula will be = $\frac{180}{60}Xempiricalformula$

molecular formula=C₉H₂₄O₃

Answer from: Quest

Standing in the sunlight and feeling the heat on your face (uv radiation is entering the skin, converting to infrared radiation, and is absorbed by your tissues)orstanding near a fire and feeling the heat on your skin (infrared radiation transfer)

Another question on Chemistry

Chemistry, 21.06.2019 20:30

If 10.g of agno3 is available, what volume of 0.25 m agno3 can be prepared

Answers: 1

Answer

Chemistry, 22.06.2019 07:30

Identify two types of chemical bonding in the source of dietary potassium

Answers: 3

Answer

Chemistry, 22.06.2019 09:00

Plz mark brainliest 30 points1) find the momentum of a 12 kg snowball that is rolling with a velocity of 9 m/s.2) an 8 ball with a mass of .5 kg is sitting at rest. it is hit by the cue ball (1 kg) traveling at 2.5 m/s. if the cue ball is at rest after the collision, how fast is the 8 ball traveling after the collision? 3) two football players are running toward each other. if the offensive player is 75 kg and is running 8 m/s, how fast must the 60 kg defensive player run in order for the two players to hit and stop?

Answers: 1

Answer

Chemistry, 22.06.2019 12:00

Which of the following is an example of physical change not a chemical change? a) a log gives off heat and light as it burns. b) a tree stores energy from the sun in its fruit. c) a penny lost in the grass slowly changes color. d) a water pipe freezes and cracks on a cold night.

Answers: 2

Answer

You know the right answer?

You perform a combustion analysis on a 255 mg sample of a substance that contains only c, h, and o,...

Questions