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Bumek [7]
3 years ago
7

Which statement is true?

Chemistry
2 answers:
AleksandrR [38]3 years ago
7 0

Exothermic reaction is where there is release of energy during a reaction

The enthalpy of exothermic reaction is negative

The relation between energy of products, reactants and enthalpy of reaction is

Enthalpy of reaction =  sum of enthalpy of formation of products - sum of enthalpy of formation of reactants .

As enthalpy of reaction is negative, it means the enthalpy of products is less than the enthalpy of reactants  so answer is :

In an exothermic reaction the energy of the product is less than the energy of the reactants.

forsale [732]3 years ago
7 0

C.

An endothermic reaction is a reaction that absorbs heat from the surroundings. That means that the energy of the system must increase. Therefore, the answer must be C as the products should have higher energy than the reactants.

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3 years ago
Why do atoms become anion and cations (remember the octet rule and how 8 is a very important number)?
Kryger [21]

Answer:

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8 0
2 years ago
The table shows the amount of radioactive element remaining in a sample over a period of time.
Assoli18 [71]

It would take 147 hours for 320 g of the sample to decay to 2.5 grams from the information provided.

Radioactivity refers to the decay of a nucleus leading to the spontaneous emission of radiation. The half life of a radioactive nucleus refers to the time required for the nucleus to decay to half of its initial amount.

Looking at the table, we can see that the initial mass of radioactive material present is 186 grams, within 21 hours, the radioactive substance decayed to half of its initial mass (93 g). Hence, the half life is 21 hours.

Using the formula;

k = 0.693/t1/2

k = 0.693/21 hours = 0.033 hr-1

Using;

N=Noe^-kt

N = mass of radioactive sample at time t

No = mass of radioactive sample initially present

k = decay constant

t = time taken

Substituting values;

2.5/320= e^- 0.033 t

0.0078 = e^- 0.033 t

ln (0.0078) = 0.033 t

t = ln (0.0078)/-0.033

t = 147 hours

Learn more: brainly.com/question/6111443

7 0
2 years ago
A student places a beaker on a hot plate. To the beaker, he adds a clear liquid and a white powder. The mixture instantly begins
Elenna [48]
True, because if it wasn't a chemical reaction it would have proceeded to stay the same. but it begins to bubble.
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7 0
3 years ago
Read 2 more answers
The purpose of a scientific investigation is
torisob [31]
Is to find the problem to the investigation
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3 years ago
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