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erica [24]
3 years ago
8

describe how the current modern atomic theory and model differs from the model jj Thompson proposed ?

Chemistry
1 answer:
myrzilka [38]3 years ago
6 0
J.J Thompson’s model shows a sphere with electrons that are moving around freely. However, Thompson’s model does not show protons or neutrons. The model that we have today gives a clearer structure showing protons, neutrons, and electrons inside an atom.
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Please help me
Wittaler [7]

Answer:

pH = 6.999

The solution is acidic.

Explanation:

HBr is a strong acid, a very strong one.

In water, this acid is totally dissociated.

HBr + H₂O  →  H₃O⁺  +  Br⁻

We can think pH, as - log 7.75×10⁻¹² but this is 11.1

acid pH can't never be higher than 7.

We apply the charge balance:

[H⁺] = [Br⁻] + [OH⁻]

All the protons come from the bromide and the OH⁻ that come from water.

We can also think [OH⁻] = Kw / [H⁺] so:

[H⁺] = [Br⁻] + Kw / [H⁺]

Now, our unknown is [H⁺]

[H⁺] =  7.75×10⁻¹² + 1×10⁻¹⁴ / [H⁺]

[H⁺] = (7.75×10⁻¹² [H⁺] + 1×10⁻¹⁴) /  [H⁺]

This is quadratic equation:  [H⁺]² - 7.75×10⁻¹² [H⁺] - 1×10⁻¹⁴

a = 1 ; b = - 7.75×10⁻¹² ; c = -1×10⁻¹⁴

(-b +- √(b² - 4ac) / (2a)

[H⁺] = 1.000038751×10⁻⁷

- log [H⁺] = pH → 6.999

A very strong acid as HBr, in this case, it is so diluted that its pH is almost neutral.

8 0
3 years ago
A teacher puts two tablets in a glass of water. The teacher
ehidna [41]

This question is incomplete because the options are missing; here are the options:

Which of the following is LESS dense than water?

The spoon

The glass

The tablets

The bubbles

The correct answer to this question is The bubbles

Explanation:

In general, the density of materials and substances affects their buoyancy. This implies in water less dense materials will float and those with higher density will sink. In the situation presented, the only element that is less dense than water are bubbles; this is shown by the movement of the bubbles as these originate in the bottom of the glass of water but they rise to the surface, which shows they are less dense than water.

6 0
3 years ago
Read 2 more answers
A glucose solution that is prepared for a patient should have a concentration of 180 g/L. A nurse has 18 g of glucose. How
Irina-Kira [14]
<h3>Answer:</h3>

0.10 L

<h3>Explanation:</h3>

The concentration of glucose  is given as 180 g/L

The mass of glucose is 18 g

  • Concentration in g/L is calculated by dividing mass of the solute by the volume of the solution.
  • When calculating molarity on the other hand, we divide number of moles of the solute by the volume  of the solution.
  • Concentration in g/L = Mass of solute ÷ Volume

Rearranging the formula,

Volume = Mass of the solute ÷ concentration

             = 18 g ÷ 180 g/L

            = 0.10 L

Therefore, volume of water is 0.10 L

6 0
3 years ago
Isn’t urgent the first 3 will be marked BRAINIEST
bearhunter [10]

Answer:

Al2(SO4)3 and Mg(OH)2

Explanation:

1. Al has a charge of 3-, and SO4 of 2-

when you cross multiply the charges you get

Al2 and (SO4)3

*the reason theres a bracket around the sulfate ion is that the charge 3 is not for oxygen only, but the entire sulphate ion*

Hence, Al2(SO4)3

2. Mg has a charge of 2- and OH of 1-

again cross multiply

Mg (you dont need to add the 1) and (OH)2

again, the bracket around OH means the charge appiles to Oxygen AND hydrogen

hence, Mg(OH)2

7 0
3 years ago
Read 2 more answers
Calculate the pKa of lactic acid (CH3CH(OH)COOH) given the following information. 3.005 grams of potassium lactate are added to
snow_lady [41]

Answer:

\displaystyle \text{p} K_a \approx 3.856

Explanation:

Because 3.005 grams of potassium lactate is added to 100. mL of solution, its concentration is:


\displaystyle \begin{aligned} \left[ \text{KC$_3$H_$_5$O$_3$}\right]  & = \frac{3.005\text{ g KC$_3$H_$_5$O$_3$}}{100.\text{ mL}} \cdot \frac{1\text{ mol KC$_3$H_$_5$O$_3$}}{128.17 \text{ g KC$_3$H_$_5$O$_3$}} \cdot \frac{1000\text{ mL}}{1\text{ L}} \\ \\ &= 0.234\text{ M}\end{aligned}

By solubility rules, potassium is completely soluble, so the compound will dissociate completely into potassium and lactate ions. Therefore, [KC₃H₅O₃] = [C₃H₅O₃⁺]. Note that lactate is the conjugate base of lactic acid.

Recall the Henderson-Hasselbalch equation:

\displaystyle \begin{aligned}\text{pH} = \text{p}K_a + \log \frac{\left[\text{Base}\right]}{\left[\text{Acid}\right]} \end{aligned}

[Base] = 0.234 M and [Acid] = 0.500 M. We are given that the resulting pH is 3.526. Substitute and solve for p<em>Kₐ</em>:

\displaystyle \begin{aligned} (3.526) & = \text{p}K_a + \log \frac{(0.234)}{(0.500)} \\ \\ 3.526 & = \text{p}K_a + (-0.330) \\ \\ \text{p}K_a & = 3.856\end{aligned}

In conclusion, the p<em>Kₐ </em>value of lactic acid is about 3.856.

5 0
1 year ago
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