The elements in each group have the same number of electrons in the outer orbital. Or also called valence electrons. Khan academy has a great video online explaining why this happens. (It only happens for main group elements). Here is a link (sorry you can’t click it in Brainly) https://www.khanacademy.org/science/chemistry/periodic-table/copy-of-periodic-table-of-elements/v/periodic-table-valence-electrons. Feel free to message me for a better explanation, I would explain now but I’m not sure how much you know about this. If you know how to write an electron configuration you can see how all the electron configurations for the same group (not the transitional metals only the main groups) have the same number of valence electrons. I hope that helped, sorry I was vague about the explanation :)
The chemical could have more or less of a reaction to the other chemicals in the experiment
Complete Question
The complete question is shown on the first uploaded image
Answer:
The concentration of 
that should used originally is 
Explanation:
From the question we are told that
The necessary elementary step is
The time taken for sixth of 0.5 M of reactant to react 
The time available is 
The desired concentration to remain 
Let Z be the reactant , Y be the first product and X the second product
Generally the elementary rate law is mathematically as
Where k is the rate constant , 
is the concentration of Z
From the elementary rate law we see that the reaction is second order (This because the concentration of the reactant is raised to power 2 )
For second order reaction
Where 
is the initial concentration of Z which a value of 
From the question we are told that it take 9 hours for the concentration of the reactant to become
So
=> 
For 
Answer:
30.8 grams of nitric acid are produced
Explanation:
Let's state the reaction:
3 NO₂ + H₂O → 2 HNO₃ + NO
If water is the excess reagent, then the limiting is the gas.
We convert the mass to moles:
45 g . 1 mol/ 46 g = 0.978 moles
Ratio is 3:2. 3 moles of gas can produce 2 moles of acid
Then, 0.978 moles may produce (0.978 . 2) /3 = 0.652 moles of acid
This is the 100% yield, but in this case, the percent yield is 75%
0.652 moles . 0.75 = 0.489 moles
Let's convert the moles to mass → 0.489 mol . 63g / 1mol = 30.8 g
Answer:
6.75 moles of CuCl₂ were used
Explanation:
Given data:
Number of moles of AlCl₃ formed = 4.5 mol
Number of moles of CuCl₂ used = ?
Solution:
Chemical equation:
3CuCl₂ + 2Al → 2AlCl₃ + 3Cu
Now we will compare the moles of CuCl₂ and AlCl₃
AlCl₃ : CuCl₂
2 : 3
4.5 : 3/2×4.5 = 6.75
6.75 moles of CuCl₂ were used.
