Answer: Elements in Group 2
Explanation: The periodic table was arranged by Dmitri Mendeleev specifically around similarites in their chemical behaviors. He found that as atomic number increases, at some point an element starts to react in a manner similar to a previous one. When that happened, he would place the larger element under the smaller one, and eventually noticed a periodicity in the table. Elements in a column (Groups) had similiar chemical properties. We know today that these similarities are due to the electron configuration, and that these configurations repeat themselves. He left gaps in the table when he could find an existing element with properties similar to others in that group. I big leap of faith, but it worked. Elements for those missing boxes were eventually discovered.
The number of moles in each sample will be 0.391 moles, 30.7 moles, 0.456 moles, and 1350 moles
<h3>What is the number of moles?</h3>
The number of moles of a substance is the ratio of the mass of the substance to the molar mass.
In other words; mole = mass/molar mass.
Thus:
- moles of 18.0 g
= 18.0/46
= 0.391 moles
- moles of 1.35 kg
= 1350/44
= 30.7 moles
- moles of 46.1 g
= 46.1/101.1
= 0.456 moles
- moles of 191.8 kg
= 191800/142
= 1350 moles
More on the number of moles of substances can be found here: brainly.com/question/1445383
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<span>The copper would go under oxidation since it will be losing two electrons. Copper starts out with an oxidation number of zero, but in order to balance the compound of CuO with the Oxygen having an oxidation number of -2, a positive 2 is required</span>
In order to find the answer you must plug in the information to the frequency equation,
. C is the speed of light, 3.0 x 10^8. By plugging in the information you receive a frequency of
3.0 x 10^7 hz.
Answer:
1.09 moles of NaOH
Explanation:
First of all, to calculate moles, you need to find the molar mass of NaOH.
Let us first find the molar mass of NaOH then.
Na = 23.0 amu
O = 16.0
H = 1.0
They are 1 nitrogen atom, 1 oxygen atom, and one hydrogen atom.
So do this.
23.0(1) + 16.0(1) + 1.0(1) = 40 g/mol.
Now use dimensional analysis to show your work
43.5 g of NaOH * 1 mol of NaOH / 40 g/mol of NaOH
The grams cancel out.
43.5 / 40.0 = 1.0875
Use sig figs and round the answer to the nearest hundredths place.
1.0875 = 1.09
So the final answer is 1.09 moles of NaOH
Hope it helped!
