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3 years ago

After an experiment, scientists write a ___ which summarizes their experiment and results

Chemistry

1 answer:

Rudiy273 years ago

6 0

After an experiment, scientists write a Conclusion which summarizes their experiment and results.

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The decomposition of N2O4 into NO2 has Kp = 2. Some N2O4 is placed into an empty container, and the partial pressure of NO2 at e

Sunny_sXe [5.5K]

Answer: Option (B) is the correct answer.

Explanation:

Expression for the given decomposition reaction is as follows.

$N_{2}O_{4} \rightarrow 2NO_{2}$

Let us assume that x concentration of $N_{2}O_{4}$ is present at the initial stage. Therefore, according to the ICE table,

$N_{2}O_{4} \rightarrow 2NO_{2}$

Initial : x 0

Change : - 0.1 $2 \times 0.1$

Equilibrium : (x - 0.1) 0.2

Now, expression for $K_{p}$ of this reaction is as follows.

$K_{p} = \frac{P^{2}_{NO_{2}}}{P_{N_{2}O_{4}}}$

Putting the given values into the above formula as follows.

$K_{p} = \frac{P^{2}_{NO_{2}}}{P_{N_{2}O_{4}}}$

$2 = \frac{(0.2)^{2}}{(x - 0.1)}$

$2 \times (x - 0.1) = (0.2)^{2}$

x = 0.12

This means that $P_{N_{2}O_{4}}$ = x = 0.12 atm.

Thus, we can conclude that the initial pressure in the container prior to decomposition is 0.12 atm.

6 0

3 years ago

A scientist measures the standard enthalpy change for the following reaction to be 67.9 kJ:

bekas [8.4K]

Answer: The standard enthalpy of formation of $H_2O(g)$ is -252.1 kJ/mol.

Explanation:

The balanced chemical reaction is,

$Fe_2O_3(s)+3H_2(g)\rightarrow 2Fe(s)+3H_2O(g)$

The expression for enthalpy change is,

$\Delta H=[n\times H_f_{products}]-[n\times H_f_{reactantss}]$

Putting the values we get :

$\Delta H=[2\times H_f{Fe}+3\times H_f{H_2O}]-[1\times H_f{Fe_2O_3}+3\times H_f{H_2}]$

$67.9kJ=[(2\times 0)+(3\times H_f{H_2O})]-[(1\times -824.2kJ/mol)+3\times 0kJ/mol)]$

$H_f{H_2O}=-252.1kJ/mol$

Thus standard enthalpy of formation of $H_2O(g)$ is -252.1 kJ/mol.

3 0

2 years ago

What causes an ice cube to melt after you take it out of the freezer? Write at least 3 sentences in your answer. INCLUDE ATTRACT

worty [1.4K]

Ice melts when heat energy causes the molecules to move faster, breaking the hydrogen bonds between molecules to form liquid water.

5 0

2 years ago

The decomposition of hydrogen peroxide follows first order kinetics and has a rate constant of 2.54 x 10-4 s-1 at a certain temp

pav-90 [236]

<u>Answer:</u> The initial concentration of hydrogen peroxide at the given temperature is 0.399 M

<u>Explanation:</u>

Decomposition of hydrogen peroxide is following first order kinetics.

Rate law expression for first order kinetics is given by the equation:

$k=\frac{2.303}{t}\log\frac{[A_o]}{[A]}$

where,

k = rate constant = $2.54\times 10^{-4}s^{-1}$

t = time taken for decay process = 855 s

$[A_o]$ = initial amount of the reactant = ?

[A] = amount left after decay process = 0.321 M

Putting values in above equation, we get:

$2.54\times 10^{-4}s^{-1}=\frac{2.303}{855s}\log \frac{[A_o]}{0.321}$

$[A_o]=0.399M$

Hence, the initial concentration of hydrogen peroxide at the given temperature is 0.399 M

7 0

3 years ago

Ort

ivanzaharov [21]

Answer:

1 ethanol is right answer

Explanation:

CH3- CH2-OH

4 0

3 years ago

Read 2 more answers