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3 years ago

Evidence of a chemical change does NOT include

Chemistry

2 answers:

Elena-2011 [213]3 years ago

4 0

C. change in shape is the right answer

horrorfan [7]3 years ago

3 0

C is the correct answer for this question. since it is a physical change

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A sample of gas has an initial volume of 3.00 L and an initial pressure of 2.14 atm. If the volume expands to 8.15 L, what is th

Alla [95]

Answer:

The final pressure is 0.788 atm (option b).

Explanation:

Boyle's law says that the volume occupied by a given gaseous mass at constant temperature is inversely proportional to pressure. That is: if the pressure increases, the volume decreases, while if the pressure decreases, the volume increases. This is expressed mathematically as the product of pressure times volume equal to a constant value:

P*V=k

Assuming a certain volume of gas V1 that is at a pressure P1 at the beginning of the experiment, by varying the volume of gas to a new value V2, then the pressure will change to P2, and it will be fulfilled:

P1*V1=P2*V2

In this case:

P1= 2.14 atm
V1= 3 L
P2= ?
V2= 8.15 L

Replacing:

2.14 atm*3 L= P2* 8.15 L

Solving:

$\frac{2.14 atm*3 L}{8.15 L} =P2$

0.788 atm= P2

<u><em>The final pressure is 0.788 atm (option b).</em></u>

6 0

3 years ago

Which molecule is shown below

rewona [7]

Answer:

Explanation:

You can see the top part looks kinda like methane, and the bottom part looks like hexane.

8 0

3 years ago

Read 2 more answers

The balanced equation for the aerobic reaction is:

Furkat [3]

Answer:

1.85 g of hydrogen gas will form!

Explanation:

1. Write the balanced equation.

2HCl

→

ZnCl

2. Calculate the moles of

Moles of Zn

30.0

g Zn

1 mol Zn

65.38

g Zn

0.4589 mol Zn

3. Calculate the moles of

Moles of H

0.4589

mol Zn

2 mol H

mol Zn

0.9177 mol H

4. Calculate the mass of

Mass of H

0.9177

mol H

2.016 g H

mol H

1.85 g H

6 0

3 years ago

Chemical reactions occur when molecules or atoms collide, the bonds between atoms are broken, and new bonds are formed.

schepotkina [342]

Answer:

A. Decreasing the temperature decreases the kinetic energy of the reactants, and the reaction goes more slowly.

C. Reactants must collide, with proper orientation, with energy greater than or equal to the activation energy for a reaction to occur.

D. Increasing the amount of reactants increases the number of collisions, and the reaction goes faster.

F. The energy of a collision between atoms or molecules must be greater than or equal to the activation energy (Ea) for bonds to be broken.

Explanation:

Decreasing the temperature decreases the kinetic energy of the reactants, so fewer molecules have enough kinetic energy to get over the Eₐ barrier, and the reaction goes more slowly.

Reactants must collide, with proper orientation, with energy greater than or equal to Eₐ for a reaction to occur.

Increasing the concentration of reactants increases the frequency of collisions, so the number of successful collisions increases.

The energy of a collision between atoms or molecules must be greater than or equal to Eₐ for bonds to be broken.

B is wrong. If Eₐ is low, more of the molecules can get over the energy barrier, and the reaction rate is fast.

E is wrong. If the energy of the products is higher than the energy of the reactants, the products must have gained energy. The reaction is endothermic.

G is wrong. Eₐ is the energy difference between the energy of the transition state and that of the reactants.

8 0

3 years ago

Which of the following description of the moons surface is accurate?

maria [59]

The answer is B) dry and irregular

4 0

4 years ago

Read 2 more answers