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2 years ago

Which of the following is most likely an indication of a chemical change?

Chemistry

1 answer:

mamaluj [8]2 years ago

5 0

Hello there!

Question: Which of the following is most likely an indication of a chemical change?

Answer Choices:

A. A loud sound when an MP3 player is turned on.

B. A loud sound when someone claps their hands.

C. A loud sound when a starter's pistol is fired at a race.

D. A loud sound when a large object falls to the ground.

Correct Answer:

C. A loud sound when a starter's pistol is fired at a race.

Reasons:

A would not be correct since an MP3 player is a mechanical object and does not mix any substances that create a reaction.

B would not be correct since clapping hands causes a loud sound due to two forces slamming together and causes a disturbance in the air.

D would not be correct since a large object falling to the ground does not indicate any chemical reactions or changes since its merely the result of a mass hitting another mass.

C would be correct since the gunpowder mixes with other substances inside the pistol's chamber and causes and explosion, and explosions are part of a chemical reaction indicators.

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Which water usage uses the least amount of water in a year in the United States

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Answer: a

Explanation:

Industry uses only about 18% while the others use around 70-90% of water.

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2 years ago

a. What condition must be met for an activated complex to result from the collision of reactant particles? b. Where, in terms of

weeeeeb [17]

Answer:

A. The conditions are:

I. Reactant particles must collide with the right orientation.

II. There must be effective collisions.

III. The reactant particles must possess enough energy to break old bonds so that new bonds can be formed.

B. The activated complex occurs where the maximum energy of the reaction is attained along the reaction pathway, that is, at the peak of the activation energy.

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3 years ago

I need help pleasee

Readme [11.4K]

Answer:

Explanation:

6. Where on the graph does adding heat energy NOT raise the temperature?

What is the heat energy DOING if it's not raising the temperature? :its being compressed I believe its vaporizing

7. What is temperature A called? Freezing

8. What is temperature B called? Vaporizing

4 0

3 years ago

A 13 g sample of P4010 contains how many

Alex777 [14]

Answer:

$\large \boxed{5.5 \times 10^{22}\text{ molecules of P$_{2}$O}_{5}}$

Explanation:

You must calculate the moles of P₄O₁₀, convert to moles of P₂O₅, then convert to molecules of P₂O₅.

1. Moles of P₄O₁₀

$\text{Moles of P$_{4}$O}_{10} = \text{13 g P$_{4}$O}_{10} \times \dfrac{\text{1 mol P$_{4}$O}_{10}}{\text{283.89 g P$_{4}$O}_{10}} = \text{0.0458 mol P$_{4}$O}_{10}$

2. Moles of P₂O₅

P₄O₁₀ ⟶ 2P₂O₅

The molar ratio is 2 mol P₂O₅:1 mol P₄O₁₀

$\text{Moles of P$_{2}$O}_{5} = \text{0.0458 mol P$_{4}$O}_{10} \times \dfrac{\text{2 mol P$_{2}$O}_{5}}{\text{1 mol P$_{4}$O}_{10}} = \text{0.0916 mol P$_{2}$O}_{5}$

3. Molecules of P₂O₅

$\text{No. of molecules} = \text{0.0916 mol P$_{2}$O}_{5} \times \dfrac{6.022 \times 10^{23}\text{ molecules P$_{2}$O}_{5}}{\text{1 mol P$_{2}$O}_{5}}\\\\= \mathbf{5.5 \times 10^{22}}\textbf{ molecules P$_{2}$O}_{5}\\\text{There are $\large \boxed{\mathbf{5.5 \times 10^{22}}\textbf{ molecules of P$_{2}$O}_{5}}$}$

6 0

3 years ago

How many grams of CH4 will be in a 500ml contain at STP?

ArbitrLikvidat [17]

Answer:

Mass = 0.32 g

Explanation:

Given data:

Mass of CH₄ = ?

Volume of CH₄ = 500 mL (500 mL× 1L/1000 mL= 0.5 L)

Temperature = 273 K

Pressure = 1 atm

Solution:

Volume of CH₄:

500 mL (500 mL× 1L/1000 mL= 0.5 L)

The given problem will be solve by using general gas equation,

PV = nRT

P= Pressure

V = volume

n = number of moles

R = general gas constant = 0.0821 atm.L/ mol.K

T = temperature in kelvin

By putting values,

1 atm× 0.5 L = n×0.0821 atm.L/ mol.K × 273 K

0.5 atm.L = n×22.4 atm.L/ mol

n = 0.5 atm.L / 22.4 atm.L/ mol

n = 0.02 mol

Mass in gram:

Mass = number of moles × molar mass

Mass = 0.02 mol × 16 g/mol

Mass = 0.32 g

7 0

3 years ago