Fireworks change blank into blank and blank energy.

Using the following thermochemical equation, determine the amount of heat produced from the combustion of 24.3 g benzene (C6H6).

Anna007 [38]

Answer:

ΔH = -976.5 kJ

Explanation:

For the reaction given, there are 2 moles of benzene (C6H6). The heat of this reaction is -6278 kJ, which means that the combustion of 2 moles of benzene will lose 6278 kJ of heat. It is an exothermic reaction.

The value of ΔH, the enthalpy, is a way of measurement of the heat, and it depends on the quantity of the matter (number of moles).

So, 24.3 g of benzene has :

n = mass/ molar mass

n = 24.3/78.11

n = 0.311 moles

2 moles ------------ -6278 kJ

0.311 moles ----------- x

By a simple direct three rule:

2x = -1953.08

x = -976.5 kJ

3 0

3 years ago

How can a weaker party impact the law making process?

I am Lyosha [343]

Answer: This is due to a dominance of political parties over ... legislative process, the influence opposition has on amending the government bills and formal and effective

Explanation: hope u get it right

5 0

3 years ago

Buffer preparation. You wish to prepare a buffer consisting of acetic acid and sodium acetate with a total acetic acid plus acet

Hoochie [10]

Answer:

0.182 moles of acetic acid are needed, this means 10.93 g.

0.318 moles of sodium acetate are needed, this means 26.08 g.

Explanation:

The Henderson–Hasselbalch (<em>H-H</em>) equation tells us the relationship between the concentration of an acid, its conjugate base, and the pH of a buffer:

pH = pka + $log\frac{[A^{-} ]}{[HA]}$

In this case, [A⁻] is the concentration of sodium acetate, and [HA] is the concentration of acetic acid. The pka is a value that can be looked up in literature: 4.76.

From the problem we know that

[A⁻] + [HA] = 250 mM = 0.250 M eq. 1

We use the <em>H-H</em> equation, using the data we know, to describe [A⁻] in terms of [HA]:

5.0 = 4.76 + $log\frac{[A^{-} ]}{[HA]}$

$0.24=log\frac{[A^{-} ]}{[HA]}\\\\10^{0.24}=\frac{[A^{-} ]}{[HA]}\\ 1.74 [HA] = [A^{-}]$ eq.2

Now we replace the value of [A⁻] in eq. 1, to calculate [HA]:

1.74 [HA] + [HA] = 0.250 M

[HA] = 0.091 M

Then we calculate [A⁻]:

[A⁻] + 0.091 M = 0.250 M

[A⁻] = 0.159 M

Using the volume, we can calculate the moles of each substance:

moles of acetic acid = 0.091 M * 2 L = 0.182 moles
moles of sodium acetate = 0.159 M * 2 L = 0.318 moles

Using the molecular weight, we can calculate the grams of each substance:

grams of acetic acid = 0.182 mol * 60.05 g/mol = 10.93 g
grams of sodium acetate = 0.318 mol * 82.03 g/mol = 26.08 g

8 0

3 years ago

A cyclist accelerates from 0 m/s to 8 m/s in 3 seconds. What is his acceleration? Is this acceleration higher than that of a car

Firlakuza [10]

<h3>Answer:</h3>

Acceleration of the cyclist: 2.67 m/s²

The acceleration of the cyclist is lower than that of the car.

<h3>Explanation:</h3>

Acceleration refers to the rate of change in velocity of a body in motion.
It is calculated by; dividing the change in velocity by time.
Acceleration = (Final velocity - Initial velocity) ÷ time

In this case;

For the cyclist;

Initial velocity = 0 m/s

Final velocity = 8 m/s

time = 3 seconds

Therefore;

Acceleration = (8 m/s - 0 m/s) ÷ 3 seconds

= 2.67 m/s²

For the car;

Initial velocity = 0 m/s
Final velocity = 30 m/s
Time = 8 seconds

Therefore;

Acceleration = ( 30 m/s - 0 m/s) ÷ 8 seconds

= 3.75 m/s²

The acceleration of the cyclist is lower than that of the car.

4 0

3 years ago

Use of fractional distillation ?

n200080 [17]

Fractinal distillation is used in the production of gasoline, distilled water, xylene, alcohol, paraffin, kerosene, and many other liquids.

3 0

4 years ago