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2 years ago

1. A fire is heating up a pot, which is cooking food. Which part of this reaction is the chemical reaction system?

1 answer:

7 0

2. When a fire is burning, chemical energy is turned into visible energy in the form of light and thermal energy in the form of heat.

3. A burning fire is exothermic because a lot of heat is given off as the wood is converted into carbon dioxide and water.

4. Energy is never created but simple recycled and changed into other forms.

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18 An important environmental consideration is the appropriate disposal of cleaning solvents. An environmental waste treatment c

Katyanochek1 [597]

Answer:

a) Percentage by mass of carbon: 18.3%

Percentage by mass of hydrogen: 0.77%

b) Percentage by mass of chlorine: 80.37%

c) Molecular formula: $C_{2} H Cl_{3}$

Explanation:

Firstly, the mass of carbon must be determined by using a conversion factor:

$0.872g CO _{2} *\frac{12g C}{44g CO_{2} } = 0.238g CO_{2}$

The same process is used to calculate the amount of hydrogen:

$0.089g H_{2}O*\frac{2g H}{18g H_{2}O } = 0.010g H$

The percentage by mass of carbon and hydrogen are calculated as follows:

%C $\frac{0.238g}{1.3g} *100%$ = 18.3%

%H $\frac{0.010g}{1.3g} *100%$ =0.77%

From the precipation data it is possible obtain the amount of chlorine present in the compound:

$1.75 AgCl*\frac{35.45g Cl}{143.45g AgCl}$ = 0.43g AgCl

Let's calculate the percentage by mass of chlorine:

%Cl= $\frac{0.43g}{0.535g} * 100%$ = 80.37%

Assuming that we have 100g of the compound, it is possible to determine the number of moles of each element in the compound:

$18.3g C*\frac{1mol C}{12g C} = 1.52mol C$

$0.77g H*\frac{1mol H}{1g H} = 0.77mol H$

$80.37gCl*\frac{1molCl}{35.45g Cl} = 2.27mol Cl$

Dividing each of the quantities above by the smallest (0.77mol), the subscripts in a tentative formula would be

$C=\frac{1.52}{0.77} = 1.97$ ≈ 2

$H = \frac{0.77}{0.77} = 1$

$Cl =\frac{2.27}{0.77}=2.94$ ≈3

The empirical formula for the compound is:

$C_{2} H Cl_{3}$

The mass of this empirical formula is:

mass of C + mass of H + mass of Cl= 24g +1+ 106.35 =131.35g

This mass matches with the molar mass, which means that the supscript in the molecular formula are the same of the empirical one.

5 0

3 years ago

Is water wet? I give you a lot of points

UkoKoshka [18]

i mean technically, no. only because water is water and water makes things wet. you know? unless you pour water onto water then idk honestly, truly...

6 0

3 years ago

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Which information in the periodic table indicates the number of protons in an atom? A. the position of the element in its c

Leni [432]

Hi there!

D is true

the number of protons is same as atomic number in an atom

good luck!

3 0

3 years ago

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Based on this chart, what percentage of energy comes from fossil fuels?

Julli [10]

Answer:

37%+24%+23%=84% , i wish my answer is correct

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3 years ago

Why are covalent substances gases and liquid rather than solids?

garri49 [273]

Covalent compounds are held together with an intra molecular attraction which is weaker than metallic bond

hence covalent compounds exist as liquids, gases and soft solids

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3 years ago