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Alik [6]
4 years ago
14

How did the discovery of isotopes help to lead to a revised model of atomic structure?

Chemistry
1 answer:
Arte-miy333 [17]4 years ago
8 0
Dalton postulated that atoms of the same elements had the same mass while atoms of different elements had different masses. 

The discovery of isotopes revealed that atoms of the same element did not necessarily have same masses, they could have different masses.

Therefore, the modern periodic table that we use nowadays contains the average atomic mass of all the isotopes found for a given element.
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Write the correct IUPAC name for each of the following structures (3 marks per
a_sh-v [17]

Answer:

Methyl group

Explanation:

From the diagram shown, we can see that the family group CH3 is attached to the structure.

This is simply called a methyl group because it is derived from me than and written that way to show the direct bonding between carbon and the 3 hydrogen atoms.

3 0
3 years ago
C. What is oxidized in the reaction? What is reduced? (2 points)
Rina8888 [55]

Answer:

Oxidation: a type of chemical reaction where one or more electrons are lost.

Oxidation State / Number: a number assigned to an atom describing its degree of oxidation, meaning how many electrons it has gained or lost.

Reduction: a type of chemical reaction where one or more electrons are gained.

Oxidation-Reduction Reaction: a chemical reaction where oxidation and reduction occurs simultaneously

Explanation:

Reduction always occurs at cathode

Oxidation always occurs in anode

These two process occurs in same way independent of nature of cell whether voltaic or electrolytic.

6 0
2 years ago
Aqueous hydrochloric acid (HCl) reacts with solid sodium hydroxide (NaOH) to produce aqueous sodium chloride (NaCl) and liquid w
Naddika [18.5K]

Answer:

87.9 % is the percent yield of H₂O

Explanation:

This is the neutralization reaction. A base reacts with an acid to produce water and the correspondly ionic salt.

NaOH  +  HCl  → NaCl +  H₂O

As we have the mass of the two reactants, we must determine the limiting reactant.

Let's convert to moles, the mass of each reactant. (mass / molar mass)

21.1 g / 36.45 g/mol = 0.579 moles of HCl

46.3 g / 40g/mol = 1.15 moles of NaOH

Ratio is 1:1, so it is obviously that the limiting reactant is the HCl. For 1.15 moles of NaOH, i need the same amount of acid, but I only have 0.579 moles

Let's work with the products now. Ratio is 1:1 again, so If I have 0.579 moles of acid, I can produce 0.579 moles of H₂O.

How many grams are 0.579 moles of water? We should find it out as this

mol . molar mass = mass → 0.579 mol . 18 g/mol = 10.4 g

We were told that the production of water was 9.17 g, so let's determine the percent yield as this:

(Yield produced / Theoretical yield) . 100 =

(9.17 g / 10.4g ) . 100 = 87.9 %

6 0
4 years ago
If 0.500 mol of each of the following solutes is dissolved in 2.0 L of water, which will cause the greatest increase in the boil
serious [3.7K]

Answer is: D. Na2SO4.

b(solution) = 0.500 mol ÷ 2.0 L.

b(solution) = 0.250 mol/L.

b(solution) = 0.250 m; molality of the solutions.

ΔT = Kf · b(solution) · i.

Kf - the freezing point depression constant.

i - Van 't Hoff factor.

Dissociation of sodium sulfate in water: Na₂SO₄(aq) → 2Na⁺(aq) + SO₄²⁻(aq).

Sodium sulfate dissociates on sodium cations and sulfate anion, sodium sulfate has approximately i = 3.

Sodium chloride (NaCl) and potassium iodide (KI) have Van 't Hoff factor approximately i = 2.

Carbon dioxide (CO₂) has covalent bonds (i = 1, do not dissociate on ions).

Because molality and the freezing point depression constant are constant, greatest freezing point lowering is solution with highest Van 't Hoff factor.

8 0
3 years ago
Read 2 more answers
The reaction below demonstrates which characteristic of a base?
svlad2 [7]

Answer: option D. the ability of a base to react with a soluble metal salt.


Justification:


NaOH is a strong base, which means that in water it will dissociate according to this reaction:


  • NaOH(aq) → Na⁺ (aq) + OH⁻ (aq)

On the other hand, CuSO₄ is a soluble ionic salt which in water will dissociate into its ions according to this other reaction:

  • CuSO₄(aq) → Cu²⁺ + SO₄²⁻

Hence, in solution, the sodium ion (Na⁺) will  react with the metal salt in a double replacement reaction, where the highly reactive sodium ion (Na⁺) will substitute the Cu²⁺ in the CuSO₄ to form the sodium sulfate salt, Na₂SO₄ (water soluble), and the copper(II) hydroxide, Cu(OH)₂ (insoluble).


That is what the given reaction represents:


  CuSO₄ (aq)     +     2NaOH(aq)    →    Cu(OH)₂(s)       +     Na₂SO₄(aq)

         ↑                                ↑                         ↑                            ↑

soluble metal salt       strong base       insoluble base       solube salt



5 0
4 years ago
Read 2 more answers
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