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3 years ago

What is Alkaline and acid

Chemistry

1 answer:

Lunna [17]3 years ago

8 0

Answer:

Alkaline is a substance that is over the pH of 7. an acid is a substance that is lower than the pH of 7

When universal indicator is put into an alkaline substance it will turn blue/purple/black. If it is an acid the substance will turn red/orange/yellow

The same will happen if litmus paper is used instaed. If the paper turns blue/purple/black it means that the substance is an alkaline. If the paper turns red/orange/yellow it means that the substance is an acid

If the substance or the litmus paper turns green it means that it is neutral (It has the pH of 7)

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8 0

2 years ago

The K w for water at 0 ∘ C is 0.12 × 10 − 14 . Calculate the pH of a neutral aqueous solution at 0 ∘ C.

dusya [7]

Answer:

pH = 7.46

Explanation:

2H₂O ⇄ H₃O⁺ . OH⁻ Kw = [H₃O⁺] . [OH⁻]

[H₃O⁺] = [OH⁻]

√0.12×10⁻¹⁴ = [H₃O⁺] → 3.46×10⁻⁸ M

- log [H₃O⁺] = pH

- log 3.46×10⁻⁸ = pH → 7.46

6 0

3 years ago

Which type of compound dissociates?

Anarel [89]

<span>Ionic compounds dissociate</span>

4 0

3 years ago

Use the data given below to construct a Born-Haber cycle to determine the second ionization energy of Ca. Δ H°(kJ) Ca(s)→Ca(g) 1

Drupady [299]

Answer : The value of second ionization energy of Ca is 1010 kJ.

Explanation :

The formation of calcium oxide is,

$Ca(s)+\frac{1}{2}O_2(g)\overset{\Delta H_f}\rightarrow CaO(s)$

$\Delta H_f^o$ = enthalpy of formation of calcium oxide = -635 kJ

The steps involved in the born-Haber cycle for the formation of $CaO$ :

(1) Conversion of solid calcium into gaseous calcium atoms.

$Ca(s)\overset{\Delta H_s}\rightarrow Ca(g)$

$\Delta H_s$ = sublimation energy of calcium = 193 kJ

(2) Conversion of gaseous calcium atoms into gaseous calcium ions.

$Ca(g)\overset{\Delta H_I_1}\rightarrow Ca^{+1}(g)$

$\Delta H_I_1$ = first ionization energy of calcium = 590 kJ

(3) Conversion of gaseous calcium ion into gaseous calcium ions.

$Ca^{+1}(g)\overset{\Delta H_I_2}\rightarrow Ca^{+2}(g)$

$\Delta H_I_2$ = second ionization energy of calcium = ?

(4) Conversion of molecular gaseous oxygen into gaseous oxygen atoms.

$O_2(g)\overset{\Delta H_D}\rightarrow OI(g)$

$\frac{1}{2}O_2(g)\overset{\Delta H_D}\rightarrow O(g)$

$\Delta H_D$ = dissociation energy of oxygen = $\frac{498}{2}=249kJ$

(5) Conversion of gaseous oxygen atoms into gaseous oxygen ions.

$O(g)\overset{\Delta H_E_1}\rightarrow O^-(g)$

$\Delta H_E_1$ = first electron affinity energy of oxygen = -141 kJ

(6) Conversion of gaseous oxygen ion into gaseous oxygen ions.

$O^-(g)\overset{\Delta H_E_2}\rightarrow O^{2-}(g)$

$\Delta H_E_2$ = second electron affinity energy of oxygen = 878 kJ

(7) Conversion of gaseous cations and gaseous anion into solid calcium oxide.

$Ca^{2+}(g)+O^{2-}(g)\overset{\Delta H_L}\rightarrow CaO(s)$

$\Delta H_L$ = lattice energy of calcium oxide = -3414 kJ

To calculate the overall energy from the born-Haber cycle, the equation used will be:

$\Delta H_f^o=\Delta H_s+\Delta H_I_1+\Delta H_I_2+\Delta H_D+\Delta H_E_1+\Delta H_E_2+\Delta H_L$

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

$-635kJ=193kJ+590kJ+\Delta H_I_2+249kJ+(-141kJ)+878kJ+(-3414kJ)$

$\Delta H_I_2=1010kJ$

Therefore, the value of second ionization energy of Ca is 1010 kJ.

6 0

3 years ago

A student used 1.2 g of hydrate in the first trial and 1.6 g in the second trial. Explain fully why her mass percent of water wi

Pachacha [2.7K]

Both trials of 1.2 g and 1.6 g will have the same mass percent of water because the ratio of the salt to the water of hydration is always constant for any hydrated salt.

<h3>Water of hydration</h3>

For every hydrated salt, the ratio of the salt to the water of hydration remains constant irrespective of the amount of salt taken for experimental analysis.

For example, assuming the mass percent of water in 10g of a hydrated salt is 40%, if 100g of the same salt is taken, the mass percent will remain 40%.

More on water of hydration can be found here: brainly.com/question/11202174

8 0

1 year ago

What is Alkaline and acid​

What is Alkaline and acid