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fenix001 [56]
3 years ago
13

39 which statement about the process of dissolving is TRUE

Chemistry
1 answer:
xz_007 [3.2K]3 years ago
6 0
C !!!!!!!!!!!!!!!!!!!!!!
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Which state of the West produces the widest varieties of fruits, vegetables, and nuts?
Yuliya22 [10]
The answer is to this question is A. California.
5 0
3 years ago
Which balanced equation represents a redox reaction?
nlexa [21]

Answer: option (3) CuO + CO ⇄ Cu + CO₂


Explanation:


1) A redox reaction is an oxidation-reduction reaction.


2) An oxidation-reduction reaction is one in which at least one species is oxidized and other (or others) is reduced.


3) Oxidation is the increase on the oxidation number, which occurs by releasing electrons.


4) Reduction is the decrease of the oxidation number, which occurs by gaining electrons.


5) By looking at the oxidation numbers of the reactants and the products you can tell whether a reaction is a redox one.


6) There are some rules to calculate the oxidation states which you need to handle to determine the oxidation states of the atoms in any chemical formula.


7) The main rule that you can use at a glance is if an element is alone in one side of the equation and is bonded to other kind of atom in the other side.


That is because the rule states that for any element that is not combined with other element its oxidation state is 0.


In this case, you can apply that rule to the equation of the choice number (3). In that, you can see that Cu is pure which as per the mentioned rule means that its oxidation state is 0.


As Cu is combined with O, CuO, in the reactant side of the chemical equation, then its oxidation number is not 0. Indeed, the rule is that in the formula CuO the oxidation states of Cu and O add up 0, and since the oxidation number of O is 2-, the oxidation number of Cu is 2+.


Therefore, having Cu changed its oxidation state from 2+ to 0, it was reduced, and this is a redox reaction.


Of course other atoms had to be oxidized. It was C whose oxidation state went from 2+ in CO to 4+ in CO₂.

7 0
2 years ago
Read 2 more answers
2. The table shows the scientific names and the common names of four plants. Which word in their names shows that two of the pla
posledela

Explanation:

the table is not given plz send the table

4 0
3 years ago
Please please help
il63 [147K]

Explanation:

question 44

the number 35 of bromine represents the atomic number

question 45

29 protons,

27 electrons

29-27 = +2

the charge on the following particle is

+2

4 0
2 years ago
A mixture containing nitrogen and hydrogen weighs 3.49 g and occupies a volume of 7.45 L at 305 K and 1.03 atm. Calculate the ma
-BARSIC- [3]

Answer:

Mass percent N₂ = 89%

Mass percent H₂ = 11%

Explanation:

First we <u>use PV=nRT to calculate n</u>, which is the total number of moles of nitrogen and hydrogen:

  • 1.03 atm * 7.45 L = n * 0.082 atm·L·mol⁻¹·K⁻¹ * 305 K
  • n = 0.307 mol

So now we know that

  • MolH₂ + MolN₂ = 0.307 mol

and

  • MolH₂ * 2 g/mol + MolN₂ * 28 g/mol = 3.49 g

So we have a <u>system of two equations and two unknowns</u>. We use algebra to solve it:

Express MolH₂ in terms of MolN₂:

  • MolH₂ + MolN₂ = 0.307 mol
  • MolH₂ = 0.307 - MolN₂

Replace that value in the second equation:

  • MolH₂ * 2 g/mol + MolN₂ * 28 g/mol = 3.49
  • (0.307-MolN₂) * 2 + MolN₂ * 28 = 3.49
  • 0.614 - 2MolN₂ + 28molN₂ = 3.49
  • 0.614 + 26MolN₂ = 3.49
  • MolN₂ = 0.111 mol

Now we calculate MolH₂:

  • MolH₂ + MolN₂ = 0.307 mol
  • MolH₂ + 0.111 = 0.307
  • MolH₂ = 0.196 mol

Finally, we convert each of those mol numbers to mass, to <u>calculate the mass percent</u>:

  • N₂ ⇒ 0.111 mol * 28 g/mol = 3.108 g N₂
  • H₂ ⇒ 0.196 mol * 2 g/mol = 0.392 g H₂

Mass % N₂ = 3.108/3.49 * 100% = 89.05% ≅ 89%

Mass % H₂ = 0.392/3.49 * 100% = 11.15% ≅ 11%

5 0
3 years ago
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