What is the chemical formula for zinc?

What is the molecular weight mass for KOH

lubasha [3.4K]

The weight is 56.1056 g/Mol hoped this helped

5 0

3 years ago

If the K a Ka of a monoprotic weak acid is 7.3 × 10 − 6 , 7.3×10−6, what is the pH pH of a 0.40 M 0.40 M solution of this acid?

olga_2 [115]

Answer:

pH =3.8

Explanation:

Lets call the monoprotic weak acid HA, the dissociation equilibria in water will be:

HA + H₂O ⇄ H₃O⁺ + A⁻ with Ka = [ H₃O⁺] x [A⁻]/ [HA]

The pH is the negative log of the H₃O⁺ concentration, we know the equilibrium constant, Ka and the original acid concentration. So we will need to find the [H₃O⁺] to solve this question.

In order to do that lets set up the ICE table helper which accounts for the species at equilibrium:

HA H₃O⁺ A⁻

Initial, M 0.40 0 0

Change , M -x +x +x

Equilibrium, M 0.40 - x x x

Lets express these concentrations in terms of the equilibrium constant:

Ka = x² / (0.40 - x )

Now the equilibrium constant is so small ( very little dissociation of HA ) that is safe to approximate 0.40 - x to 0.40,

7.3 x 10⁻⁶ = x² / 0.40 ⇒ x = √( 7.3 x 10⁻⁶ x 0.40 ) = 1.71 x 10⁻³

[H₃O⁺] = 1.71 x 10⁻³

Indeed 1.71 x 10⁻³ is small compared to 0.40 (0.4 %). To be a good approximation our value should be less or equal to 5 %.

pH = - log ( 1.71 x 10⁻³ ) = 3.8

Note: when the aprroximation is greater than 5 % we will need to solve the resulting quadratic equation.

4 0

3 years ago

Is my answer right?

Ahat [919]

Yes the answer is 1s22s22p63s23p64s23d5

7 0

2 years ago

Select the correct answer. Elements Electronegativity aluminum (Al) 1.61 calcium (Ca) 1 carbon (C) 2.55 chlorine (Cl) 3.16 fluor

marishachu [46]

Answer: Fe - O

Explanation:

1) Start by showing the chart information in a more understandable way:

Elements ---------- Electronegativity

aluminum (Al) ----- 1.61

calcium (Ca) ------- 1

carbon (C) ---------- 2.55

chlorine (Cl) -------- 3.16

fluorine (F) --------- 4

hydrogen (H) ------ 2.2

iron (Fe) ------------- 1.83

nitrogen (N) --------- 3.04

oxygen (O) ----------- 3.44

phosphorus (P) ----- 2.19

potassium (K) -------- 0.82

silicon (Si) ------------- 1.9

sulfur (S) --------------- 2.58

2) Find the electronegativity differences for the atoms in each compound:

i) Ca – Cl: 3.16 - 1 = 2.16

ii) Fe – O: 3.44 - 1.83 = 1.61

iii) H – S: 2.58 - 2.2 = 0.38

iii= F – F = 4 - 4 = 0

3) Analysis

i) The higher the electronegativity difference between two non-metal elements, the the more the polar the covalent bond. Therefore, the bond H - S is the most polar among the non-metal - non-metal bonds listed. But 0.38 is a small difference, so this is not very polar.

ii) For metal - non-metal bonds, when the difference in electronegativities is too high (close to or greater than 2.0) the ionic character is dominant, and so you cannot classify the bond as polar but as ionic. Therefore, Ca - Cl with 2.16 electronegativity difference is a ionic bond.

iii) The bond in Fe – O has electronegativty difference of 1.61, so it is yet covalent, and highly polar.

Read more on Brainly.com - brainly.com/question/1309389#readmore

8 0

2 years ago

Read 2 more answers

Which of the following will reduce copper?<br> zinc<br> mercury<br> fluorine<br> chlorine

laiz [17]

Zinc because the only metals that would be able to reduce copper ions in solution would be hydrogen, lead, tin, nickel, iron, zinc, aluminum, Magnesium, sodium, calcium, potassium, and lithium. and according to your answer choices Zinc is the answer.

4 0

3 years ago

Read 2 more answers