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3 years ago

There is about 1.0 g of calcium as Ca2+ in 1.0 L of milk. What is the molarity of Ca2+ in milk?

Chemistry

1 answer:

meriva3 years ago

7 0

Explanation:

It is known that molarity is the number of moles present in a liter of solution.

Molarity = $\frac{\text{no. of moles}}{volume}$

Also, number of moles equal mass divided by molar mass. And, molar mass of calcium is 40.07 g/mol.

No. of moles = $\frac{mass}{\text{molar mass}}$

= $\frac{1.0 g}{40.07 g/mol}$

= 0.025 mol

Therefore, calculate the molarity as follows.

Molarity = $\frac{\text{no. of moles}}{volume}$

= $\frac{0.025 mol}{1.0 L}$

= 0.025 M

Thus, we can conclude that molarity of $Ca^{2+}$ in milk is 0.025 M.

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Maurinko [17]

Answer:

$KNO_3 (aq)$

Explanation:

Potassium nitrate is a soluble salt which readily dissolves in a polar solvent, such as water. When solid potassium nitrate is dissolved in water, it dissociates into potassium cations and nitrate anions.

Due to the resultant ionic charges, the polar water molecules attract the resultant ions and potassium nitrate ions become hydrated, that is, surrounded by water molecules.

Nitrate, our anion, attracts the partially positive ends of water molecules by attracting them via hydrogen atom.

Potassium, the cation, attracts the partially negative end of water molecules by attracting via oxygen atom.

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3 years ago

6. Lysozyme is an enzyme that hydrolyzes sugar linkages in the bacterial cell wall and was first discovered by Alexander Fleming

balu736 [363]

Answer:

See explaination

Explanation:

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3 years ago

Why is the energy supplied by the cooker greater than that calculated ?

TEA [102]

Answer:

Explanation:

Q1.

(a) 46 200

accept 46 000

allow 1 mark for correct substitution

ie 0.5 × 4200 × 22 provided no subsequent step

(b) Energy is used to heat the kettle.

[3]

Q2.

(a) (approximate same size particles as each other and as liquid and gas) touching

do not accept particles that overlap

regular arrangement (filling the square)

(b) condensing

(d) physical

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particles move faster

(f) mass of the liquid

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(g) 2 × 4 200 × 801

672 000 (J)

an answer of 672 000 (J) scores 2 marks

[11]

Q3.

(a) x-axis labelled and suitable scale

Page 12 of 13

points plotted correctly

allow 5 correctly plotted for 2 marks, 3−4

correctly plotted for 1 mark

allow ± ½ square

line of best fit

(b)

allow ecf from line of best fit in part (a)

0.075 (°C/s)

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an answer of 15.525 (kJ) or 15.53 (kJ) or 15.5

(kJ) scores 4 marks

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[10]

Q4.

(a) 80 °C

ΔE = 0.5 × 3400 × 80

ΔE = 136 000 (J)

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allow any correct description of wasted energy

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(d) efficiency = 300/500

efficiency = 0.6

an answer of 0.6 or 60% scores 2 marks

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an answer of 0.6 with a unit scores 1 mark

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2 years ago

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Daniel [21]

The total pressure when the new equilibrium is stabilized is half of the initial pressure of the system.

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2H₂O(g)+O₂(g) = 2H₂O₂(g)

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PV = nRT

P is pressure,

V is volume,

n is moles

R is gas constant,

T is temperature.

Assuming the temperature is constant.

If the volume of the system is twice the initial volume then the total pressure at the new equilibrium can be found out as,

P₁V₁ = P₂V₂

Where, P₁ and V₁ are initial volume and pressure while P₂ and V₂ are final pressure and volume.

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11 months ago

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kozerog [31]

Answer:

solubility

Explanation:

Solubility is the ability of a solid, liquid, or gaseous chemical substance (referred to as the solute) to dissolve in solvent (usually a liquid) and form a solution. The solubility of a substance fundamentally depends on the solvent used, as well as temperature and pressure.

<em>hope it helps :)</em>

<em>please mark it the brainliest!</em>

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3 years ago