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4 years ago

#1: Which scientist is credited with developing the orbital model of the atom?

1 answer:

4 0

Niels Henrik David Bohr is the scientist credited with developing the orbital model of the atom. He was Danish physicist who made foundational contributions to understanding atomic structure and quantum theory. He received the Nobel Prize in Physics in 1922

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When performing a flame test using the method described in the manual, you complete the flame test of KNO3 and find a yellow col

jolli1 [7]

Answer:

The nichrome wire is dirty.

The solution is contaminated.

Explanation:

If the nichrome wire is dirty, it may contain sodium contaminants which may be responsible for the yellow flame. The nichrome wire is first inserted into the flame without the sample to check for impurities.

The test solution may also have been contaminated. This leads to the appearance of a colour different from the expected colour of the test cation in the solution.

7 0

3 years ago

the water in a tea pot is heated on a stove top. The temperature of the water increases. Is this an endothermic or exothermic pr

marusya05 [52]

It is an endothermic process

5 0

3 years ago

5000kg of ammonium nitrate per square kilometer of cornfield per year. how much nitric acid would be needed to make the fertiliz

Serggg [28]

$NH_3+HNO_3-> NH_4NO_3$

1 mole of nitric acid produce 1 mole of ammonium nitrate.

moles in 5000 kg of ammonium nitrate :

$n=\dfrac{5000\times 1000}{80}\\\\n=62500\ moles$ ( molecular mass of ammonium nitrate is 80 gm/mol )

So, number of moles of nitric acid required are also 62500 moles.

Mass of 62500 moles of nitric acid :

$mass = 62500\times 63 \\\\mass = 3937500\ gram\\\\mass = 393.75\ kg$

Hence, this is the required solution.

5 0

3 years ago

Hydrazine (N2H4), a rocket fuel , reacts with oxygen to form nitrogen gas and water vapor. The reaction is represented with the

lilavasa [31]

Answer:

D) 8.40 L H₂O(g).

Explanation:

The balanced equation for the mentioned reaction is:

2N₂H₄(l) + O₂(g) → N₂(g) + 2H₂O(g),

It is clear that 2.0 moles of N₂H₄ react with 1.0 mole of O₂ to produce 2.0 moles of N₂ and 2.0 moles of H₂O.

At STP, 4.20L of O₂ reacts with N₂H₄:

It is known that at STP: every 1.0 mol of any gas occupies 22.4 L.

using cross multiplication: 

1.0 mol of O₂ represents → 22.4 L.

??? mol of O₂ represents → 4.2 L.

∴ 4.2 L of O₂ represents = (1.0 mol)(4.2 L)/(22.4 L) = 0.1875 mol.

To find the no. of moles of H₂O produced:

Using cross multiplication:

1.0 mol of O₂ produce → 2.0 mol of H₂O, from stichiometry.

0.1875 mol of O₂ produce → ??? mol of H₂O.

∴ The no. of moles of H₂O = (2.0 mol)(0.1875 mol)/(1.0 mol) = 3.75 mol.

Again, using cross multiplication:

1.0 mol of H₂O represents → 22.4 L, at STP.

3.75 mol of H₂O represents → ??? L.

∴ The no. of liters of water vapor will be produced = (3.75 mol)(22.4 L)/(1.0 mol) = 8.4 L.

So, the right choice is: D) 8.40 L H₂O(g).

3 0

3 years ago

Will the water level of the sea increase when there is global warming

alexdok [17]

Global warming will cause see levels to rise since a lot of water is stored in ice sheets which will melt. All of the melt water will end up in the ocean causing sea levels to rise.

I hope this helps. Let me know if anything is unclear.

8 0

3 years ago