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3 years ago

8

How long will it take the Sun to go around the galaxy once? a. 200 million years c. 100 thousand years b. 10 years d. 5 billion

years

2 answers:

USPshnik [31]3 years ago

4 0

200 million years it will take this long and this proves how long the sun will possibly last

kirill [66]3 years ago

3 0

The answer is 200 million years

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Explain the role light plays on the rate<br> of photosynthesis.

Luda [366]

Answer:

The process of photosynthesis occurs when green plants use the energy of light to convert carbon dioxide (CO2) and water (H2O) into carbohydrates. Light energy is absorbed by chlorophyll, a photosynthetic pigment of the plant, while air containing carbon dioxide and oxygen enters the plant through the leaf stomata.

5 0

3 years ago

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

A 50 kg skater pushed by a friend accelerates 5 m/sec2. How much force did the friend apply?

DENIUS [597]

Answer:

$\underline{ \boxed{f = 250 \: N}}$

Explanation:

$since \: force \ \: : \underline{ \boxed{f = ma}} \\ f = 50 \times 5 \\ \underline{ f = 250 \: N}$

♨Rage♨

5 0

3 years ago

Consider the following unbalanced redox reaction:

Greeley [361]

Answer:

Two

Explanation:

I believe your unbalanced equation should be

H₂O₂ + I₂ ⟶ IO₃⁻

The half-reactions and the overall reaction are:

5 × [H₂O₂ + 2H⁺ +2e⁻ ⟶ 2H₂O]

1 × <u>[ I₂ + 6H₂O ⟶ 2IO₃⁻ + 12H⁺ + 10e⁻] </u>

5H₂O₂ + I₂ ⟶ 2IO₃⁻ + 2H⁺ + 4H₂O

The reaction needs two hydrogen ions for balancing.

4 0

3 years ago

The cell theory states that all living things are composed of one or more cells that carry out the functions needed to support l

saw5 [17]

Answer:

New cells arise from existing cells.

Explanation:

According to the cell theory, "all living things are composed of one or more cells; the cell is the basic unit of life; and new cells arise from existing cells"(Lumen Learning).

Cells are the basic unit of life. Some organisms consists of only one cell while other organisms have many cells and are called multicellular organisms.

In multicellular organisms, new cells are formed by the division of preexisting cells.

7 0

3 years ago