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2 years ago

A solid substance turns directly into a gas. Which term describes this change?

Chemistry

2 answers:

IgorLugansk [536]2 years ago

5 0

Answer:

sublimation

Explanation:

Deposition is like dew forming

evaporation is going from liquid to gas

melting is going form solid to liquid ( like ice does when it warms)

sublimation is going from solid directly to gas ( like moth balls)

Aliun [14]2 years ago

3 0

It’s probably A or D.

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_____ can be defined as the rate at which velocity changes

sergejj [24]

Answer: Acceleration can be defined as the rate at which velocity changes

Acceleration has the units m/s2.

Hope this helps! :D

5 0

3 years ago

Read 2 more answers

Blast furnaces extra pure iron from the Iron(IIl)oxide in iron ore in a two step sequence. In the first step, carbon and oxygen

OLga [1]

Answer:

5.9 kg

Explanation:

We must work backwards from the second step to work out the mass of oxygen.

1. Second step

Mᵣ: 55.84

Fe₂O₃ + 3CO ⟶ 2Fe + 3CO₂

m/kg: 7.0

(a) Moles of Fe

$\text{Moles of FeO} = \text{7000 g Fe} \times \dfrac{\text{1 mol Fe}}{\text{55.84 g Fe}} = \text{125 mol Fe}$

(b) Moles of CO

$\text{Moles of CO} = \text{125 mol Fe} \times \dfrac{\text{3 mol CO}}{\text{2 mol Fe}} = \text{188 mol CO}$

However, this is the theoretical yield.

The actual yield is 72. %.

We need more CO and Fe₂O₃ to get the theoretical yield of Fe.

(c) Percent yield

$\begin{array}{rcl}\text{Percent yield} &=& \dfrac{\text{ actual yield}}{\text{ theoretical yield}} \times 100 \, \%\\\\ 72. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.72 &= &\dfrac{\text{188 mol}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{188 mol}}{0.72}\\& = & \textbf{261 mol}\\\\\end{array}$

We must use 261 mol of CO to get 7.0 kg of Fe.

2. First step

Mᵣ: 32.00

2C + O₂ ⟶ 2CO

n/mol: 261

(a) Moles of O₂

$\text{Moles of O}_{2} = \text{261 mol CO} \times \dfrac{\text{1 mol O}_{2}}{\text{2 mol CO}} = \text{131 mol O}_{2}$

(b) Mass of O₂

$\text{Mass of O}_{2}= \text{131 mol O }_{2} \times \dfrac{\text{32.00 g O}_{2}}{\text{1 mol O}_{2}} = \text{4180 g O}_{2}$

However, this is the theoretical yield.

The actual yield is 71. %.

We need more C and O₂ to get the theoretical yield of CO.

(c) Percent yield

$\begin{array}{rcl}71. \, \% & = & \dfrac{\text{188 mol}}{\text{actual yield}} \times 100 \,\%\\\\0.71 &= &\dfrac{\text{4180 g}}{\text{actual yield}}\\\\\text{Actual yield} & = & \dfrac{\text{4180 g}}{0.71}\\\\& = & \text{5900 g}\\& = & \textbf{5.9 kg}\\\end{array}$

We need 5.9 kg of O₂ to produce 7.0 kg of Fe.

6 0

4 years ago

What is measurement?<br>

Alexus [3.1K]

Measurement is a process of finding a number that shows the amount of something.

Brainliest? Thanks!

6 0

3 years ago

Read 2 more answers

I NEED HELP PLEASE, THANKS!

ira [324]

Answer:

About 0.652

Explanation:

Because the reaction is balanced, we can go straight to the next step. The molar mass of potassium is about 39.098, while the molar mass of hydrogen gas is 2 and the molar mass of water is 18. Therefore, 25.5g of potassium would be about 0.652 moles, and 220 grams of water would be about 12.222 moles, making potassium the limiting reactant. Since there is a single unit of each compound on both sides of the equation, there would be an equal amount of moles of potassium and hydrogen, and therefore about 0.652 moles of hydrogen gas would be produced. Hope this helps!

6 0

3 years ago

Except for speed, your nervous system is most similar to

dlinn [17]

Your nervous system is most similar to a cruise ship (option C).

The nervous system is a complex network in the body in charge of:

Automatic responses and movements.
Voluntary movements.
Responses to the world.

This system works due to the action of structures such as:

The brain.
The spinal cord.
The nerves.

Moreover, the nervous system works through the following steps:

A stimulus is received, for example, you accidentally touch a hot surface.
This is taken by the nerves to the brain.
The brain processes the information and sends a response, for example, to move the hand away from the hot surface.

Based on this, the system resembles a cruise ship because signals go from the senses to the brain and then back again similar to a cruise going away and then back to the port.

Learn more about brain in: brainly.com/question/5361122

8 0

2 years ago