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3 years ago

EASY 100 POINTS, WILL MARK BRAINLEST, 2 QUESTIONS, SHOW YOUR WORK OR NO POINTS

Chemistry

2 answers:

disa [49]3 years ago

8 0

Answer:

Explanation:

1 c. enthalpy change = enthalphies of formation of all products - enthalphies of formation of all reactants = -526.3 kcal/mol

1 d. C3H8(g) + 5 O2 (g) → 3 CO2 (g) + 4 H2O (l) ΔH = -526.3 kcal/mol

SVETLANKA909090 [29]3 years ago

5 0

Answer:

Explanation:

1. Please provide the enthalpy info - I will work on it with the info

i) Reaction a should be modified to match the number of S in equation:

2S + 2O2 -> 2SO2 deltaH = -370kJ

ii) Reaction b should be written reversely to match the reactants of SO2:

2SO2 + O2 -> 2SO3 deltaH = 256kJ

iii) Adding the equations together:

2S + 3O2 -> 2SO3

iv) Enthalpy of the combined reaction = -370+256 = -114kJ

It is negative so the reaction is exothermic.

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NaOH has a molarity of 2.5 M and a volume of 4 Liters, how many moles are in the solution?

Inga [223]

Answer:

10. mol NaOH

Explanation:

2.5 M = 2.5 mol/L

2.5 mol/L * 4 L = 10. mol

7 0

3 years ago

The first word in the name of an ester is derived from the ________ used in the esterification.

oksian1 [2.3K]

The first word in the name of an ester is derived from the alcohol used in the esterification.

<h3>What is esterification?</h3>

Esterification is a chemical process where an organic acid with the formula is combined with an alcohol molecule having the chemical formula (ROH).

The process of esterification is known to produce an ester molecule and during this phenomenon is released water (H2O).

An example of an esterification reaction occurs when ethanoic acid (i.e., the active ingredient of vinegar) can react with C2H5OH (i.e., ethanol) in order to form the ethyl ethanoate molecule, which is a well-known ester molecule.

In conclusion, the first word in the name of an ester is derived from the Alcohol used in the esterification.

Learn more about esterification here:

brainly.com/question/14028062

#SPJ1

8 0

2 years ago

A 13.30 gram sample of an organic compound containing C, H and O is analyzed by combustion analysis and 13.00 grams of CO2 and 2

a_sh-v [17]

Answer: The empirical and molecular formula for the given organic compound is $CHO_2$ and $C_2H_2O_4$

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 $CO_2=13.00g$

Mass of $H_2O=2.662g$

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 13.00 g of carbon dioxide, $\frac{12}{44}\times 13.00=3.54g$ of carbon will be contained.

For calculating the mass of hydrogen:

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

So, in 2.662 g of water, $\frac{2}{18}\times 2.662=0.296g$ of hydrogen will be contained.

Mass of oxygen in the compound = (13.30) - (3.54 + 0.296) = 9.464 g

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

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{3.54g}{12g/mole}=0.295moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{0.296g}{1g/mole}=0.296moles$

Moles of Oxygen = $\frac{\text{Given mass of oxygen}}{\text{Molar mass of oxygen}}=\frac{9.465g}{16g/mole}=0.603moles$

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 0.295 moles.

For Carbon = $\frac{0.295}{0.295}=1$

For Hydrogen = $\frac{0.296}{0.295}=1$

For Oxygen = $\frac{0.603}{0.295}=2.044\approx 2$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : O = 1 : 1 : 2

Hence, the empirical formula for the given compound is $CHO_2$

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 = 90.04 g/mol

Mass of empirical formula = 45 g/mol

Putting values in above equation, we get:

$n=\frac{90.04g/mol}{45g/mol}=2$

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

$C_{(1\times 2)}H_{(1\times 2)}O_{(2\times 2)}=C_2H_2O_4$

Hence, the empirical and molecular formula for the given organic compound is $CHO_2$ and $C_2H_2O_4$

3 0

3 years ago

EXTRA CREDIT. The rate at which an object moves is its speed. If a horse

Irina18 [472]

Average speed is total distance divided by total time.

Total distance is 50 m + 150 m + 300 m = 500 m
Total time is 68 s + 35 s + 22 s = 125 s

Average speed is 500 m / 125 s = 4 m/s

6 0

3 years ago

What is peristalsis? PLEASE HELPP

ladessa [460]

Answer:

Muscular contractions that moves food along the digestive tract.

5 0

3 years ago

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