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3 years ago

If an element has the atomic number 20, what sub levels are present

1 answer:

8 0

Atomic number = 20 -------> Ca (calcium)

Calcium has four shells (1, 2, 3, 4) and two sublevels ( s, p ).

1s² 2s² 2p⁶ 3s² 3p⁶ 4s²

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QUESTION 1 (POLL)

Airida [17]

Answer:

They stay the same

Explanation:

4 0

3 years ago

13. When a train car traveling at 4 m/s collides with a stationary train car, what happens to the momentum of the first train ca

Solnce55 [7]

Answer:

Momentum of first train car will reduce

Explanation:

When the moving care collides with the stationary car, it will increase the momentum of the stationary car. However, its own momentum will reduce.

It is so because the speed of the first train car will reduce after collision due to loss of energy in the collision while the stationary car may gain some momentum due to rise in velocity from zero (velocity at stationary position).

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3 years ago

When benzene (c6h6) reacts with bromine (br2) bromobenzene(c6h5br) is obtained: c6h6 + br2 → c6h5br + hbr what is the theoretica

saveliy_v [14]

Answer A) : We have to calculate the number of moles of Benzene involved in the reaction,

30 g / 78 moles of benzene = 0.384 moles

For bromine it will be the same process,

65 g / 159.8 moles = 0.406 moles

By observing the reaction given above we can say that the reaction ratio of bromine and benzene is 1 : 1

We need to find the mass of bromobenzene,

which should be, 6(12) + 5 (1)+ 79.90 = 156.9 g/mol

So, the mass of bromobenzene will be 156.9 g/mol X 0.3846 mol = 60.343 g

Hence the theoretical yield will be 60.34 g

Answer B) : To calculate the actual yield we have to divide it with theoretical yield.

(56.7g / 60.343 g ) X100% = 93.96 %

Here, we can say that we got 93.96 % of actual yield.

As we know it is impossible to get 100% yield in any reaction.

3 0

3 years ago

1 mol Fe2(CrO4)3=____g

IgorLugansk [536]

111.6g of Fe + 156g of Cr + 192g of O = 459.6g of Fe2(CrO4)3

7 0

3 years ago

- Standard state refers to

yulyashka [42]

Answer: The standard state refers to 1 atm and $25^{o}C$ .

Explanation:

It is known that a chemical/substance can either be present in a solid, liquid or gaseous state.

So, when the phase of a substance like solid, liquid or gas is present at 1 atmosphere pressure and at a temperature of $25^{o}C$ then it known as standard state of substance.

Thus, we can conclude that standard state refers to 1 atm and $25^{o}C$ .

4 0

3 years ago