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melisa1 [442]
3 years ago
7

Which of the following statements is true about atoms?

Chemistry
1 answer:
Leokris [45]3 years ago
6 0

Atoms of the same element may have different mass numbers.

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1.35 m solution NaOCl in water is prepared. What is the mole fraction of the NaOCl?
MAXImum [283]

Answer:

NaOCl + H2O → HOCl + NaOH

so the mole fraction is = moles of NaOCl/(moles of NaOCl+moles of H2O)

so for 1.35 NaOCl it will require 1.35 moleof H2O

mole fraction = 1.35/(1.35+1.35)

mole fraction = 1/2 =0.5

is it correct i d ek but i tried :)

4 0
3 years ago
Why is petrified wood considered a fossil?
earnstyle [38]

Answer:

Petrified wood was part of a plant that has been changed into rocks.

Explanation:

Yeet

5 0
3 years ago
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Is this true or false ?
stiks02 [169]

Answer:

false

Explanation:

The atom model has changed over time because of the discovery of subatomic particles

7 0
3 years ago
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A weak monoprotic acid is titrated with 0.100 MNaOH. It requires 50.0 mL of the NaOH solution to reach the equivalence point. Af
larisa86 [58]

Explanation:

The given reaction is as follows.

        HA(aq) + NaOH (aq) \rightleftharpoons NaA(aq) + H_{2}O(l)

Hence, number of moles of NaOH are as follows.

        n = 0.05 L \times 0.1 M

           = 0.005 mol

After the addition of 25 ml of base, the pH of a solution is 3.62. Hence, moles of NaOH is 25 ml base are as follows.

             n = 0.025 L \times 0.1 M

                = 0.0025 mol

According to ICE table,

         HA(aq) + NaOH (aq) \rightleftharpoons NaA(aq) + H_{2}O(l)

Initial:     0.005 mol   0.0025 mol              0                  0

Change: -0.0025 mol  -0.0025 mol        +0.0025 mol

Equibm:   0.0025 mol    0                         0.0025 mol

Hence, concentrations of HA and NaA are calculated as follows.

          [HA] = \frac{0.0025 mol}{V}

        [NaA] = \frac{0.0025 mol}{V}

       [A^{-}] = [NaA] = \frac{0.0025 mol}{V}

Now, we will calculate the pK_{a} value as follows.

          pH = pK_{a} + log \frac{A^{-}}{HA}

       pK_{a} = pH - log \frac{[A^{-}]}{[HA]}

                  = 3.42 - log \frac{\frac{0.0025 mol}{V}}{\frac{0.0025}{V}}

                  = 3.42

Thus, we can conclude that pK_{a} of the weak acid is 3.42.

           

8 0
3 years ago
You were asked to determine the identity of an unknown liquid and can measure only one physical property. you heat the liquid an
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I did this before and i had got an A no it but its been along time tho
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