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3 years ago

What is true about energy?

2 answers:

7 0

The correct answer is option A. Energy cannot be created during an ordinary chemical reaction. There is no such thing as an ordinary chemical reaction. Energy cannot be created or destroyed this is according to the law of conservation of energy. It can only be transformed from one form to another form.

kirill [66]3 years ago

7 0

Among these statements, the correct notion about energy is that energy cannot be created during an ordinary chemical reaction. this follows the law of conservation of mass which states that energy is neither created nor destroyed in any processes.

You might be interested in

Carbon, hydrogen and ethane each burn exothermically in an excess of air. AHⓇ =-393.7 kJ mol. C(s) + O2(g) → CO2(g) H2(g) + % O2

Salsk061 [2.6K]

<u>Answer:</u> The $\Delta H^o_{rxn}$ for the reaction is 51.8 kJ.

<u>Explanation:</u>

Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.

According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.

The chemical equation for the reaction of carbon and water follows:

$2C(s)+2H_2(g)\rightarrow C_2H_4(g)$ $\Delta H^o_{rxn}=?$

The intermediate balanced chemical reaction are:

(1) $C(s)+O_2(g)\rightarrow CO_2(g)$ $\Delta H_1=-393.7kJ$ ( × 2)

(2) $H_2+\frac{1}{2}O_2(g)\rightarrow H_2O(l)$ $\Delta H_2=-285.9kJ$ ( × 2)

(3) $2C_2H_4(s)+2O_2(g)\rightarrow 2CO_2(g)+2H_2O(l)$ $\Delta H_3=-1411kJ$

The expression for enthalpy of the reaction follows:

$\Delta H^o_{rxn}=[2\times \Delta H_1]+[2\times \Delta H_2]+[1\times (-\Delta H_3)]$

Putting values in above equation, we get:

$\Delta H^o_{rxn}=[(2\times (-393.7))+(2\times (-285.9))+(1\times -(-1411))]=51.8kJ$

Hence, the $\Delta H^o_{rxn}$ for the reaction is 51.8 kJ.

6 0

3 years ago

Solve this word problem:

valina [46]

Answer:

The new acceleration becomes twice the pervious acceleration.

Explanation:

Given that,

Mass of the rock, m = 3 kg

Force, F = 1 N

We know that the force acting on an object is given by :

F = ma

a is acceleration of the rock

Put m = 3 kg and F = 1N,

$a=\dfrac{F}{m}\\\\a=\dfrac{1}{3}\ m/s^2$

If the force is doubled, F' = 2 N

So,

F'=ma'

$a'=\dfrac{F'}{m}\\\\a'=\dfrac{2\times 1}{3}\\\\a'=\dfrac{2}{3}\\\\a'=2\times \dfrac{1}{3}\\\\a'=2a$

So, the new acceleration becomes twice the initial acceleration.

3 0

3 years ago

Each of the four liquids had the same volume. Why didn’t

Alexeev081 [22]

Bdjdisisididiieddiidid

5 0

2 years ago

I need help can you help

telo118 [61]

I can sure try to help!

8 0

2 years ago

What is the molarity of a solution containing 8.9 g of NaOH in 550. mL of NaOH solution?

bulgar [2K]

Answer:

0.4 M

Explanation:

Molarity is defined as moles of solute, which in your case is sodium hydroxide,

NaOH

, divided by liters of solution.

molarity

moles of solute

liters of solution

Notice that the problem provides you with the volume of the solution, but that the volume is expressed in milliliters,

Moreover, you don't have the number of moles of sodium hydroxide, you just have the mass in grams. So, your strategy here will be to

determine how many moles of sodium hydroxide you have in that many grams

convert the volume of the solution from milliliters to liters

So, to get the number of moles of solute, use sodium hydroxide's molar mass, which tells you what the mass of one mole of sodium hydroxide is.

⋅

1 mole NaOH

40.0

0.175 moles NaOH

The volume of the solution in liters will be

500

⋅

1 L

1000

0.5 L

Therefore, the molarity of the solution will be

0.175 moles

0.5 L

0.35 M

Rounded to one sig fig, the answer will be

0.4 M

Explanation:

6 0

2 years ago