Write the following number using Scientific notation : 13,215,296.50 *

The Ka for acetic acid (HC2H3O2) is 1.80 x 10-5 . Determine the pH of a 0.0500mol/L acetic acid solution.

TiliK225 [7]

Answer:

pH = 3.02

Explanation:

Acetic Acid is a weak acid (HOAc) that ionizes only ~1.5% as follows:

HOAc ⇄ H⁺ + OAc⁻.

In pure water the hydronium ion concentration [H⁺] equals the acetate ion concentration [OAc⁻] and can be determined* using the formula [H⁺] = [OAc⁻] = SqrRt(Ka·[acid]) = SqrRt(1.8x10⁻⁵ x 0.0500)M = 9.5x10⁻⁴M.

By definition, pH = -log[H⁺] = -log(9.5x10⁻⁴) = 3.02

______________________________________________________

*This formula can be used to determine the [H⁺] & [Anion⁻] concentrations for any weak acid in pure water given its Ka-value and the molar concentration of acid in solution.

8 0

2 years ago

If 3.89 × 1024 atoms of a noble gas is collected and it has a mass of of 848 grams, this element is most likely a. He b. Ne c. A

bearhunter [10]

Answer:

Xenon

Explanation:

Avogadro’s number represent the number of the constituent particles which are present in one mole of the substance. It is named after scientist Amedeo Avogadro and is denoted by $N_0$ .

Avogadro constant:-

$N_a=6.023\times 10^{23}$

Let the molar mass of the element is x g/mol

So,

$6.023\times 10^{23}$ atoms have a mass of x g

Also,

$3.89\times 10^{24}$ atoms have a mass of $\frac{x}{6.023\times 10^{23}}\times 3.89\times 10^{24}$ g

This mass is equal to 848 g

So,

$\frac{x}{6.023\times 10^{23}}\times 3.89\times 10^{24}=848$

x= 131.3 g/mol

This mass correspond to xenon.

3 0

3 years ago

Chemical formula for sodium and sulfur

Nookie1986 [14]

The chemical formula for sodium and sulfur is Na2S I believe...

8 0

2 years ago

State whether the sign of the entropy change expected for each of the following processes will be positive or negative, and expl

Strike441 [17]

Answer:

a) ΔS is negative

b) ΔS is positive

c) ΔS is positive

d) ΔS is negative

Explanation:

Entropy (S) is a thermodynamic parameter which measures the randomness or the disorder in a system. Greater the disorder more positive will be the value of entropy.

The extent of disorder increases as substances transition from the solid to the gaseous state. i.e.

S(solid) < S(liquid) < S(gas)

The entropy change for a given reaction is:

$\Delta S = S(products)-S(reactants)----(1)$

a) $PCl3(l) + Cl2(g) \rightarrow PCl5(s)$

Here the reactants are in the liquid and gas phase which have higher entropy than the product which is in the solid phase i.e. lower entropy.

Since S(product) < S(reactant), based on equation 1, ΔS will be negative.

b) $2HgO(s) \rightarrow 2Hg(l) + O2(g)$

Here the products are in the liquid and gas phase which have higher entropy than the reactant which is in the solid phase i.e. lower entropy.

Since S(product) > S(reactant), based on equation 1, ΔS will be positive.

c) $H2(g) \rightarrow 2H(g)$

Here the products and reactants are in the gas phase. However the number of moles of products is greater than the reactants

Since S(product) > S(reactant), based on equation 1, ΔS will be positive.

d) $U(s) + 3F2(g) \rightarrow UF6(s)$

Here one of the reactants is in the gas phase which corresponds to a more positive entropy compared to the product which is in the solid phase i.e. lower entropy.

Since S(product) < S(reactant), based on equation 1, ΔS will be negative.

8 0

2 years ago

Hey I need help with this element, compound, and mixtures worksheet

Alika [10]

We should describe a little bit the legend.

A - Element - we should have circles with same color and not bonded together (argon gas).

B - Compound - here we may have circles with same or different color bonded together (water or oxygen which is a diatomic molecule).

C - Mixture of elements - circles with different colors not not bonded together (mixture of noble gases).

D - Mixture of compounds - circles with same or different color bonded together but we should see two or more types of connectivity between circles (mixture of water and ethanol).

E - Mixture of elements and compounds - circles with same or different color bonded together mixed with circles with same color and not bonded together (a mixture between oxygen which is a diatomic molecule and noble gas like argon).

Now we may answer the question:

1) B

2) C

3) D

4) D

5) A

6) B

7) B

8) E

9) E

10) D

11) B

12) D

13) D

14) D

15) D

7 0

3 years ago

Write the following number using Scientific notation : 13,215,296.50 *​

Write the following number using Scientific notation : 13,215,296.50 *