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2 years ago

11

Which of the following is true about hydropower? It changes the surrounding ecosystem. It does not produce greenhouse gases. It

produces harmful radiation. It burns fossil fuels.

1 answer:

Whitepunk [10]2 years ago

3 0

Answer:

A

Explanation:

One of the main complaints about hydropower is that it will change the ecosystem. You can read about the history of any dam and you will find that most of them have involved evacuation. That means that farmland was lost and replaced by a lake behind the dam. The energy comes from water cascading over the top of the dam to its bottom.

It does not produce radiation.

It does not burn fossil fuels. It's clean and does not pollute the air.

So there are no greenhouse gases involoved.

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2. Chromium+oxygen - chromium(III) oxide <br>balanced

sesenic [268]

Answer:

4Cr + 3O2 —> 2Cr2O3

Explanation:

Information from the question include:

Chromium + oxygen -> chromium(III) oxide

From the word equation given above, the equation can be written as follow:

Cr + O2 —> Cr2O3

The equation can be balance by doing the following:

There are 2 atoms of O on the left side and 3 atoms on the right side. It can be balance by putting 2 in front of Cr2O3 and 3 in front of O2 as shown below:

Cr + 3O2 —> 2Cr2O3

Now, we have 4 atoms of Cr on the right side and 1 atom on the left. It can be balance by putting 4 in front of Cr as shown below:

4Cr + 3O2 —> 2Cr2O3

Now the equation is balanced

3 0

2 years ago

Convert 4.500000000 to scientific notation

aniked [119]

I think it’s 4.5 x 10^9

7 0

2 years ago

A mixture of gaseous reactants is put into a cylinder, where a chemical reaction tums them into gaseous products. The cylinder h

erastova [34]

Answer:

The reaction is exothermic

The temperature of the water bath goes up

Explanation:

An exothermic reaction is one in which energy flows out of the reaction system.

In this case, the system is the reaction vessel while the surrounding is the water bath. We see in the question that 300.1J of heat flows out of the system during the reaction. This is heat lost to the surroundings showing that the reaction is exothermic.

As energy is lost to the surroundings, the temperature of the water bath rises accordingly.

6 0

2 years ago

Air at 7S°F and14.6 though a cfm(cubic ft per minute) and the The flow rate is 48000 psia flows though a rectangular duct of Ix2

IgorLugansk [536]

Explanation:

The given data is as follows.

Air is at $75^{o}F$ and 14.6 psia.

$\varepsilon$ = 0.00015 ft, Flow rate, (Q) = 48000 $ft^{3}/m$

(a) Formula to calculate hydraulic radius $(r_{H})$ is as follows.

$r_{H} = \frac{\text{free flow area}}{\text{wet perimeter}}$

= $\frac{2 \times 1}{2(1) + 2(2)}$

= $\frac{1}{3}$ ft

Formula for equivalent diameter is as follows.

$D_{eq} = 4 \times r_{H}$

= $4 \times \frac{1}{3} ft$

= $\frac{4}{3}$ ft

(b) Formula for velocity floe is as follows.

Q = VA

V = $\frac{Q}{A}$

= $\frac{48000}{2 \times 1}$ ft/min

= 24000 ft/min

(c) Formula to calculate Reynold's number is as follows.

$R_{e}$ = $\frac{D \times V \times \rho}{\mu}$

= $\frac{\frac{4}{3} \times 24000 \times 0.0744}{0.0443}$ (as $\rho = 0.0744 lb/ft^{3}$ and $\mu$ = 0.0443 lb/ft. hr)

= 53742.66 hr/min

As 1 hr = 10 min. So, $53742.66 hr/min \times \frac{60 min}{1 hr}$

= 3224559.6

(d) Formula to calculate pressure drop $(\Delta P)$ is as follows.

$\frac{\Delta P}{L} = \frac{4f \rho V^{2}}{2Dg_{c}}$

Putting the given values into the above formula as follows.

$\frac{\Delta P}{L} = \frac{4f \rho V^{2}}{2Dg_{c}}$

= $\frac{4 \times 0.00015 \times 100 \times 0.0744 \times (24000)^{2}}{2 \times \frac{4}{3} \times {4}{3}}$

= 6.238 $lb/ft^{2}$

5 0

3 years ago

One of the main goals of environmental science is to help humans use the environment in a way that is economically profitable.

kkurt [141]

Answer:

true this is correct its your econimically

5 0

2 years ago