Chemistry Middle School


Which best explains why a firework being ignited is an example of an exothermic reaction and not an endothermic reaction?

A)The fireworks produce colors.

B)The fireworks give off heat.

C)Igniting the fireworks requires energy

D)Igniting the fireworks makes an odor.​

Answers

Answer 1

Answer:B

Explanation:

TOOK DA TEST

Answer 2

As the firework releases heat, it is considered as exothermic reaction. The correct option is B.

What is exothermic reaction?

An exothermic reaction is one in which the energy required to break bonds in the reactants is less than the energy released when new bonds form in the products.

Energy is constantly released during an exothermic reaction, often in the form of heat. Exothermic reactions characterize all combustion reactions.

Endothermic reactions are chemical reactions that produce products by absorbing heat energy from their surroundings.

Exothermic reactions are important in forensic science, particularly in the investigation of fires and explosions.

Endothermic refers to a chemical reaction that requires heat and results in cooling of the surroundings.

As fireworks are releasing energy in the form of heat, it can be called as an exothermic reaction.

Thus, the correct option is B.

For more details regarding exothermic reaction, visit:

https://brainly.com/question/10373907

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Related Questions

Which of the following chemical reactions is reversible?
A. The burning of wood.
OB. The dehydration of copper sulfate (CuSO4).
O C. The neutralization of an acid.
OD. The freezing of water into ice
Reset Selection

Answers

D the freezing of water into ice
d freezing water into ice because once the ice melts it’s water again

1. Find the volume ( cm3) of oxygen in: a. 1000cm3 of air b. 50 cm3 of air.

Answers

Answer:

A. 210 cm³

B. 10.5 cm³

Explanation:

It is important for us to note that air contains 21% of oxygen, O2. With this idea in mind, let us answer the questions given above.

A. Volume of air = 1000 cm³

Volume of O2 in air =.?

Percentage composition of O2 in air = 21%

Volume of O2 = 21% x 1000

Volume of O2 = 21/100 x 1000

Volume of O2 = 210 cm³

Therefore, the volume of O2 in 1000 cm³ of air is 210 cm³.

B. Volume of air = 50 cm³

Volume of O2 in air =.?

Percentage composition of O2 in air = 21%

Volume of O2 = 21% x 50

Volume of O2 = 21/100 x 50

Volume of O2 = 10.5 cm³

Therefore, the volume of O2 in 50 cm³ of air is 10.5 cm³.

How many molecules are in each sample?
A. 4.9 g H2O
B. 54.4 g N^2
C. 89 g CCI4
D. 11 g C6H12O6

Answers

Answer:

To find the number of molecules first find the number of moles.

number of moles (n) = mass / molar mass (M)

then use the formula

N = n × L

where n = number of moles

N = number of entities

L = Avogadro's constant = 6.02 × 10^23entities to find the number of molecules

A. 4.9 g H2O

m = 4.9g

M = (2*1)+(16×1) = 2 + 16 = 18g/mol

n = 4.9/18 = 0.272mol

N = 0.272 × 6.02 × 10^23

= 1.6374*10^23 molecules of H2O

B. 54.4g of N2

m = 54.4g

M(N2) = 14×2 = 28g/mol

n = 54.4/28 = 1.942mol

N = 1.942 * 6.02*10^23

= 1.1690*10^24 molecules of N2

C. 89 g CCI4

m = 89g

M(CCl4) = 12 + (35.5 × 4) = 154g/mol

n = 89/154 = 0.577mol

N = 0.577 × 6.02 × 10^23

= 3.473*10^23 molecules of CCl4

D. 11 g C6H12O6

m = 11g

M(C6H12O6) = (12×6)+(12×1)+(16×6) =

180g/mol

n = 11/180 = 0.0611mol

N = 0.0611 × 6.02×10^23

= 3.678*10^22 molecules of C6H12O6

Hope this helps

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