Answer:
Rb+
Explanation:
Since they are telling us that the equivalence point was reached after 17.0 mL of 2.5 M HCl were added , we can calculate the number of moles of HCl which neutralized our unknown hydroxide.
Now all the choices for the metal cation are monovalent, therefore the general formula for our unknown is XOH and we know the reaction is 1 equivalent acid to 1 equivalent base. Thus we have the number of moles, n, of XOH and from the relation n = M/MW we can calculate the molecular weight of XOH.
Thus our calculations are:
V = 17.0 mL x 1 L / 1000 mL = 0.017 L
2.5 M HCl x 0.017 L = 2.5 mol/ L x 0.017 L = 0.0425 mol
0.0425 mol = 4.36 g/ MW XOH
MW of XOH = (atomic weight of X + 16 + 1)
so solving the above equation we get:
0.0425 = 4.36 / (X + 17 )
0.7225 +0.0425X = 4.36
0.0425X = 4.36 -0.7225 = 3.6375
X = 3.6375/0.0425 = 85.59
The unknown alkali is Rb which has an atomic weight of 85.47 g/mol
Answer:
24m/s
Explanation:
a=change of v/change of t
6m/s^2=v/4s
multiply both sides by 4s
v=24m/s
Answer: the second option: <span>Iron is being oxidized
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Explanation:
1) Oxidation is the increase of the oxidation state (number) due to the loss of electrons.
2) In the given reaction, you can see that in the left side the atom is Fe.
When an element (atom) is not combined (or combined with it self) its oxidation state is 0.
3) In the right side of the given equation you that iron is now in form of cation with charge 2+: Fe²⁺.
That means that the new oxidation state of the element is 2+.
4) This change in the oxidation state, of course, is accompanied by the loss of the two electrons: 2e⁻.
5) Conclusion: the iron has oxidized by losing two electrons and increasing its oxidation state from 0 to 2+.
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Assume 1 liter = 1 kilogram of water = 1000 grams of water.
Part A)
MW of hydrogen is 1.008g/mol, and oxygen is 16.00g/mol.
Find the MW of water by
2*(1.008) + (16.00) = 18.016g/mol.
Convert 1000g H2O to moles :
(1000g H2O)*(1mol H2O / 18.016g H2O) = 55.51 mol
Part B)
Using the answer from part A and Avogadro's number:
(55.51mol)*(6.022*10^23) =
3.343*10^25 molecules.
Hope this is helpful
Answer -C They are defined by the number of electrons.
An orbital is a function that describes the probability of finding the electron with certain energy at certain distance from the nucleus therefore, it is defined by the number of electrons.
