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3 years ago

Which of the following natural resources cant be reused

1 answer:

6 0

Hi there! Air and sunlight can definitely be reused. Those are abundant and renewable resources. Therefore, A and D are eliminated. There is a limited amount of water, however, it's impossible to run out of it to the point that there's no more on Earth. C is out. The only answer choice that makes sense is coal, because it's a nonrenewable resource, and it takes millions of years to make more of. It's a fossil fuel, so once we use them up, we can't get anymore during our lives. The answer is B: coal.

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Balance the equation

saveliy_v [14]

Explanation:

3C3+2H4+9O=3CO3+4H29o

8 0

3 years ago

Which one of Newton's Laws fits this statement: More mass means more force needed to accelerate?

ivolga24 [154]

Answer:

Newton's Second Law

Explanation:

Newton's second law basically states that the acceleration of a body which is produced by a net force is directly proportional to the magnitude of net force applied in the same direction.

This tells us that

F is directly proportional to a

⇒ F= ma

So we can also state from the above equation, that when we have more mass, we need more net force to accelerate it. Here, we are keeping the acceleration constant so we can surely say that force and mass varies directly.

Therefore, we have made good use of Newton's Second Law of motion to arrive at this conclusion.

4 0

4 years ago

Consider these elements: N, Mg, O, F, Al. a. Write the electron configuration for each element. b. Arrange the elements in order

My name is Ann [436]

Answer:

N- 1s2 2s2 2p3

Mg- 1s2 2s2 2p6 3s2

O- 1s2 2s2 2p4

F- 1s2 2s2 2p5

Al-1s2 2s2 2p6 3s2 3p1

Explanation:

Order of decreasing atomic radius

Mg,Al, N,O,F

Order of increasing ionization energy

Mg,Al, N,O,F

Reason:

Atomic radius decreases with increase in nonmetallic character. Looking at the electronic configurations, as effective nuclear charge increases, the atom becomes smaller and the attractive force between the nucleus and the outermost electrons increases. Hence, the radius of the atom decreases and ionization energy increases. Note that the addition of more orbital electrons implies addition of more nuclear charge since the both must exactly balance for the atom to remain electrically neutral. The more the electrons in the outermost shell, the higher the first ionization energy.

4 0

3 years ago

An isotope of cesium-137 has a half-life of 30 years. If 5.0g of cesium-137 decays over 60 years. How many grams will remain.

LenKa [72]

Answer:

1.25 gram of cesium-137 will remain.

Explanation:

Given data:

Half life of cesium-137 = 30 year

Mass of cesium-137 = 5.0 g

Mass remain after 60 years = ?

Solution:

Number of half lives passed = Time elapsed / half life

Number of half lives passed = 60 year / 30 year

Number of half lives passed = 2

At time zero = 5.0 g

At first half life = 5.0 g/2 = 2.5 g

At 2nd half life = 2.5 g/ 2 = 1.25 g

Thus. 1.25 gram of cesium-137 will remain.

6 0

3 years ago

Balance the following redox equation in acidic solution using the smallest integers possible and select the correct coefficient

romanna [79]

Answer:

Coefficient of $H^{+}(aq)$ is more than 4

Explanation:

Oxidation: $Sn^{2+}(aq)\rightarrow Sn^{4+}(aq)$

Balance charge: $Sn^{2+}(aq)-2e^{-}\rightarrow Sn^{4+}(aq)$ ......(1)

Reduction: $Cr_{2}O_{7}^{2-}(aq)\rightarrow Cr^{3+}(aq)$

Balance Cr: $Cr_{2}O_{7}^{2-}(aq)\rightarrow 2Cr^{3+}(aq)$
Balance O and H in acidic medium: $Cr_{2}O_{7}^{2-}(aq)+14H^{+}(aq)\rightarrow 2Cr^{3+}(aq)+7H_{2}O(l)$
Balance charge: $Cr_{2}O_{7}^{2-}(aq)+14H^{+}(aq)+6e^{-}\rightarrow 2Cr^{3+}(aq)+7H_{2}O(l)$ .......(2)

$[3\times Equation-(1)]+Equation(2)$ gives balanced equation:

$3Sn^{2+}(aq)+Cr_{2}O_{7}^{2-}(aq)+14H^{+}(aq)\rightarrow 3Sn^{4+}(aq)+2Cr^{3+}(aq)+7H_{2}O(l)$

So coefficient of $H^{+}(aq)$ is more than 4

3 0

3 years ago