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2 years ago

What is the total number of atoms in one unit (molecule or formula unit) of nacl?

1 answer:

6 0

<span>One mol of NaCl (6.02 x1023 formulas) has a mass of 58.44 g. Concept 2. The relation between molecular (formula) mass and molar mass. To obtain one mole of copper atoms (6.02 x 1023 atoms), weigh out 63.55 g copper.</span>

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Uranium-267 undergoes alpha decay, what is the mass of the new element?

Firlakuza [10]

Answer:

will this help ?

Explanation:

(108Hs) is a synthetic element, and thus a standard atomic weight cannot be given. Like all synthetic elements, it has no stable isotopes. The first isotope to be synthesized was 265Hs in 1984. There are 12 known isotopes from 263Hs to 277Hs and 1–4 isomers. The most stable isotope of hassium cannot be determined based on existing data due to uncertainty that arises from the low number of measurements. The confidence interval of half-life of 269Hs corresponding to one standard deviation (the interval is ~68.3% likely to contain the actual value) is 16 ± 6 seconds, whereas that of 270Hs is 9 ± 4 seconds. It is also possible that 277mHs is more stable than both of these, with its half-life likely being 110 ± 70 seconds, but only one event of decay of this isotope has been registered as of 2016.[1][2].

3 0

2 years ago

Another simple question and I need it bad

podryga [215]

Oh this is extremely hard...i might just die lol jk its the last one measuring cylinder :)

3 0

2 years ago

Read 2 more answers

Calculate the pH after 10 mL of 1.0 M sodium hydroxide is added to 60 mL of 0.5M acetic acid.

baherus [9]

Explanation:

It is given that the total volume is (10 mL + 60 mL) = 70 mL.

Also, it is known that $M_{1}V_{1}$ = $M_{2}V_{2}$

Where, $V_{1}$ = total volume

$V_{2}$ = initial volume

Therefore, new concentration of $CH_{3}COOH$ = $\frac{M_{2}V_{2}}{V_{1}}$

= $\frac{60 \times 0.5}{70}$

= 0.43 M

New concentration of NaOH = $\frac{M_{2}V_{2}}{V_{1}}$

= $\frac{10 \times 1.0}{70}$

= 0.14 M

So, the given reaction will be as follows.

$CH_{3}COOH + OH^{-} \rightarrow CH_{3}COO^{-} + H_{2}O$

Initial: 0.43 0.14 0

Change: -0.14 -0.14 0.14

Equilibrium: 0.29 0 0.14

As it is known that value of $pK_{a}$ = 4.74

Therefore, according to Henderson-Hasselbalch equation calculate the pH as follows.

pH = $pK_{a} + log \frac{[CH_{3}COO^{-}]}{[CH_{3}COOH]}$

= $4.74 + log \frac{0.14}{0.29}$

= 4.74 + (-0.316)

= 4.42

Therefore, we can conclude that the pH of given reaction is 4.42.

6 0

2 years ago

Which radioactive isotopes did the Curies discover?

Sergio [31]

The answer is 1 polonium and radium

7 0

2 years ago

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A generic salt, AB 2 , has a molar mass of 345 g/mol and a solubility of 8.70 g/L at 25 °C. AB 2 (s) − ⇀ ↽ − A 2 + (aq) + 2B − (

Brrunno [24]

Answer : The value of $K_{sp}$ of the generic salt is, $1.60\times 10^{-5}$

Explanation :

As we are given that, a solubility of salt is, 8.70 g/L that means 8.70 grams of salt present in 1 L of solution.

First we have to calculate the moles of salt $(AB_2)$

$\text{Moles of }AB_2=\frac{\text{Mass of }AB_2}{\text{Molar mass of }AB_2}$

Molar mass of $AB_2$ = 345 g/mol

$\text{Moles of }AB_2=\frac{8.70g}{345g/mol}=0.0252mol$

Now we have to calculate the concentration of $A^{2+}\text{ and }B^-$

The equilibrium chemical reaction will be:

$AB_2(s)\rightleftharpoons A^{2+}(aq)+2B^-(aq)$

Concentration of $A^{2+}$ = $\frac{0.0252mol}{1L}=0.0252M$

Concentration of $B^-$ = $\frac{0.0252mol}{1L}=0.0252M$

The solubility constant expression for this reaction is:

$K_{sp}=[A^{2+}][B^-]^2$

Now put all the given values in this expression, we get:

$K_{sp}=(0.0252M)\times (0.0252M)^2$

$K_{sp}=1.60\times 10^{-5}$

Thus, the value of $K_{sp}$ of the generic salt is, $1.60\times 10^{-5}$

8 0

3 years ago