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3 years ago

What is the role of the beaver in its ecosystem?

2 answers:

5 0

Creating Wetlands. When beavers make a dam, they slow the flow of water in the stream and, subsequently, a pond or area of wetland is formed. Roughly 85 percent off all native North American fauna rely on wetlands, so they're extremely important to the ecosystem.

Nikolay [14]3 years ago

4 0

I think its b im pretty sure

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Why do scientists use different types of models to represent compounds

shutvik [7]

Because they are different they all show different traits

5 0

3 years ago

Read 2 more answers

What are three reasons why a population might change?

Tom [10]

If people have children, If people die, and if there is a fire or volcanic eruption.

4 0

3 years ago

How does air above a heated surface move?

anzhelika [568]

When air is warmed up, its molecules move faster and faster and as a result they move further from each other. They still have the same mass, but they now occupy a larger volume. This means that its density is smaller.
The opposite when air is cooled off. The molecules slow down, get closer together, occupy a smaller volume and therefore its density is bigger.

When air is warmed up, it goes up. Once it's up there, is cools off and goes back down. Near the heated surface the air gets warmed up again, goes up, cools down, goes back down, and again and again.
that is called convection cells

6 0

3 years ago

What is the molarity if I take 10mL of 20 volumes Hydrogen Peroxide?

Kryger [21]

Answer:

1.635 M

Explanation:

Given:

10 mL of 20 volumes Hydrogen Peroxide

Here,

20 volumes of Hydrogen Peroxide means that on decomposition of 1 mL of H₂O₂ 20 mL of O₂ is obtained

also,

means 1 dm³ of H₂O₂ solution produces 20 dm³ oxygen

Now,

at 298K and 1 atm

20 dm³ oxygen = $\frac{\textup{20}}{\textup{24.47}}$ moles

= 0.817 moles

also,

2H₂O₂ → 2H₂O + O₂

thus,

1 dm³ of solution must contain 2 × moles of O₂ as moles of H₂O₂

thus,

Number of moles of H₂O₂ = 2 × 0.817

Number of moles of H₂O₂ = 1.635 moles

Hence,

For 20 volume hydrogen peroxide is 1.635 M

3 0

3 years ago

When 125 mL of 0.150 M Pb(NO3)2 is mixed with 145 mL of 0.200 M KBr, 4.92 g of PbBr2 is collected. Calculate the percent yield.

Semenov [28]

Answer:

Y = 92.5 %

Explanation:

Hello there!

In this case, since the reaction between lead (II) nitrate and potassium bromide is:

$Pb(NO_3)_2+2KBr\rightarrow PbBr_2+2KNO_3$

Exhibits a 1:2 mole ratio of the former to the later, we can calculate the moles of lead (II) bromide product to figure out the limiting reactant:

$0.125L*0.150\frac{molPb(NO_3)_2}{L} *\frac{1molPbBr_2}{1molPb(NO_3)_2} =0.01875molPbBr_2\\\\0.145L*0.200\frac{molKBr}{L} *\frac{1molPbBr_2}{2molKBr} =0.0145molPbBr_2$

Thus, the limiting reactant is the KBr as it yields the fewest moles of PbBr2 product. Afterwards, we calculate the mass of product by using its molar mass:

$0.0145molPbBr_2*\frac{367.01gPbBr_2}{1molPbBr_2} =5.32gPbBr_2$

And the resulting percent yield:

$Y=\frac{4.92g}{5.32g} *100\%\\\\Y=92.5\%$

Regards!

4 0

3 years ago