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3 years ago

Study the reactions.

Chemistry

1 answer:

REY [17]3 years ago

8 0

Answer:

B) by first reversing Reaction 2 and then adding the enthalpy of Reaction 1 and the enthalpy of Reaction 2

Explanation:

C2H2 (g)+2H2 (g)→C2H6 (g) ΔH=−75 kcal

C2H4 (g)+H2 (g)→C2H6 (g) ΔH=−33 kcal

C2H2 (g)+H2 (g)→C2H4 (g) ΔH= ?

First step - Reverse reaction 2.

C2H6 (g) → C2H4 (g) + H2 (g) ΔH= 33 kcal

Second step - Add reaction 1 and the reversed reaction 2. This gives us:

C2H2 (g) + 2H2 (g) + C2H6 (g) → C2H6 (g) + C2H4 (g) + H2 (g)

Simplifying gives:

C2H2 (g)+H2 (g)→C2H4 (g)

The correct option is:

B) by first reversing Reaction 2 and then adding the enthalpy of Reaction 1 and the enthalpy of Reaction 2

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Give me a statement regarding the process of science discovery and development of atomic theory

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Can you say please? Just kidding!
The process of science discovery depends upon changing your theories based upons new evidence from new experiments. New technology allows for new experiments, leading to new theories.

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3 years ago

Which metalloid has three valence electrons? 1. Lithium 2. boron 3. silicon 4. aluminum 5. arsenic

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Answer:

boron

Explanation:

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3 years ago

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For a tablet containing 500. mg of vitamin C, calculate how many ml of 0.095 M NaOH is required to reach the equivalence point.

Gala2k [10]

Answer:

mL of NaOH required =29.9mL

Explanation:

Let us calculate the moles of vitamin C in the tablet:

The molar mass of Vitamin C is 176.14 g/mole

$moles=\frac{mass}{molarmass}=\frac{500mg}{176.14}=\frac{0.5}{176.14}=0.0028$

Thus we need same number of moles of NaOH to reach the equivalence point.

For NaOH solution:

$moles=MolarityXvolume=0.095Xvolume$

$0.00283=0.095Xvolume$

$volume=0.0299L=29.9mL$

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3 years ago

A laboratory analysis of a sample finds it is composed of 38.8% carbon, 16.2% hydrogen, and 45.1% nitrogen. What is its empirica

Sladkaya [172]

Answer: The empirical formula for the given compound is $CH_5N$

Explanation : Given,

Percentage of C = 38.8 %

Percentage of H = 16.2 %

Percentage of N = 45.1 %

Let the mass of compound be 100 g. So, percentages given are taken as mass.

Mass of C = 38.8 g

Mass of H = 16.2 g

Mass of N = 45.4 g

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

Step 1: Converting the given masses into moles.

Moles of Carbon = $\frac{\text{Given mass of Carbon}}{\text{Molar mass of Carbon}}=\frac{38.8g}{12g/mole}=3.23moles$

Moles of Hydrogen = $\frac{\text{Given mass of Hydrogen}}{\text{Molar mass of Hydrogen}}=\frac{16.2g}{1g/mole}=16.2moles$

Moles of Nitrogen = $\frac{\text{Given mass of nitrogen}}{\text{Molar mass of nitrogen}}=\frac{45.4g}{14g/mole}=3.24moles$

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 3.23 moles.

For Carbon = $\frac{3.23}{3.23}=1$

For Hydrogen = $\frac{16.2}{3.23}=5.01\approx 5$

For Oxygen = $\frac{3.24}{3.23}=1.00\approx 1$

Step 3: Taking the mole ratio as their subscripts.

The ratio of C : H : N = 1 : 5 : 1

Hence, the empirical formula for the given compound is $C_1H_5N_1=CH_5N$

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3 years ago

What change causes a substance to change states of matter?

pochemuha

If the states of matter have changed such as from solid to liquid, you have to remove or add energy.

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2 years ago

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