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2 years ago

Consider the reaction described by the following chemical equation.

Chemistry

1 answer:

oee [108]2 years ago

6 0

Answer:

Q = -897 kJ/mol

Explanation:

From the given information:

The heat released Q = -65.9 kJ

To start with the molar mass of $H_2O_2$ = 2 × (molar mass of H) + 2 × (molar mass of O)

= (2 × 1.008) + (2 × 16.0 )

= 34.016 g/mol

However, given that:

mass of $H_2O_2$ 2.50 g

The number of moles of $H_2O_2$ = $\dfrac{mass}{molar \ mass}$

$= \dfrac{2.5}{34.016}$

$= 7.349 \times 10^{-2} \ mol$

Finally; Using the formula:

$\Delta H = \dfrac{Q}{number \ of \ moles}\\ \\ Q = \dfrac{-65.9 \ kJ}{7.349 \times 10^{-2} \ mol}$

Q = -897 kJ/mol

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you are investigating an organic compound. you discover the following: it contains no hydrogen atoms. what property do you expec

pashok25 [27]

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CCl₄, C₂F₆.

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3 years ago

Read 2 more answers

An archer pulls her bowstring back 0.370 m by exerting a force that increases uniformly from zero to 264 N. (a) What is the equi

Arte-miy333 [17]

Answer:

713.51 N/m

Explanation:

Hook's Law: This law states that provided the elastic limit is not exceeded, the extension in an elastic material is directly proportional to the applied force.

From hook's law,

F = ke ...........................Equation 1

Where F = Force exerted on the bowstring, e = Extension/compression of the bowstring, k = Spring constant of the bow.

Make k the subject of the equation,

k = F/e ............................ Equation 2

Given: F = 264 N, e = 0.37 m.

Substitute into equation 2

k = 264/0.37

k = 713.51 N/m

Hence the spring constant of the bow = 713.51 N/m

3 0

2 years ago

How many grams of dry nh4cl need to be added to 2.50 l of a 0.800 m solution of ammonia, nh3, to prepare a buffer solution that

tia_tia [17]

Answer:

The correct answer is 574.59 grams.

Explanation:

Based on the given information, the number of moles of NH₃ will be,

= 2.50 L × 0.800 mol/L

= 2 mol

The given pH of a buffer is 8.53

pH + pOH = 14.00

pOH = 14.00 - pH

pOH = 14.00 - 8.53

pOH = 5.47

The Kb of ammonia given is 1.8 * 10^-5. Now pKb = -logKb,

= -log (1.8 ×10⁻⁵)

= 5.00 - log 1.8

= 5.00 - 0.26

= 4.74

Based on Henderson equation:

pOH = pKb + log ([salt]/[base])

pOH = pKb + [NH₄⁺]/[NH₃]

5.47 = 4.74 + log ([NH₄⁺]/[NH₃])

log([NH₄⁺]/[NH₃]) = 5.47-4.74 = 0.73

[NH₄⁺]/[NH₃] = 10^0.73= 5.37

[NH₄⁺ = 5.37 × 2 mol = 10.74 mol

Now the mass of dry ammonium chloride required is,

mass of NH₄Cl = 10.74 mol × 53.5 g/mol

= 574.59 grams.

8 0

3 years ago

What characteristics do the elements in a group share? In a period, share?

Katyanochek1 [597]

Answer:

The elements in same period have same principle quantum number or energy shell.

The elements in same group shows similar chemical and properties.

Explanation:

Inn group:

The elements in same group i.e present in vertical column shows similar chemical properties.

The elements in same group having same number of valance electrons. while in chemical reaction bonds are break and formed and valance electrons are involved. That's why elements in same group having same number of valance electrons and shows similar chemical properties.

In period:

While as we move from left to right the number of valance electron increase by one in every element. But the electron is added in same shell which means that their physical and chemical properties are different but principal quantum number is same.

3 0

3 years ago

What is the acceleration of a 50kg object pushed with a force of 500 Newton’s

olasank [31]

Answer:

Explanation:

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

$a = \frac{f}{m} \\$

f is the force

m is the mass

From the question we have

$a = \frac{500}{50} = \frac{50}{5} = 10 \\$

We have the final answer as

Hope this helps you

5 0

3 years ago