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pogonyaev
3 years ago
12

Classify each of the following as a pure substance or a mixture; if it is a mixture, state whether it is heterogeneous

Chemistry
1 answer:
Juli2301 [7.4K]3 years ago
6 0

Answer:

(a) Heterogeneous mixture; (b) heterogeneous mixture;

(c) heterogeneous mixture; (d) homogeneous mixture; (e) pure substance.

Explanation:

(a) Concrete

Heterogeneous mixture. Concrete is a mixture of sand, gravel, and crushed stone held together with a cement.

In a heterogeneous mixture, you can see definite boundaries between the various components.  

(b) Tomato juice

Heterogeneous mixture. It consists of water, tomato pulp, salt, and other substances.

(c) Marble

Heterogeneous mixture. It consists mostly of CaCO₃, but it usually contains other substances such as mica, quartz, pyrite, and iron oxides.  

(d) Seawater

Homogeneous mixture. Seawater is an aqueous solution of NaCl along with other ions like Mg²⁺, Ca²⁺ ,and SO₄²⁻.

(e) Iron

Pure substance. Iron is an element. It consists only of Fe atoms.

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150 ml of 0.1 m naoh is added to 200 ml of 0.1 m formic acid, and water is added to give a final volume of 1 l. what is the ph o
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Number of moles of NaOH = V(NaOH) * M(NaOH)= 0.150 L * 0.1 moles/L = 0.015 moles

Number of moles of formic acid, HCOOH = V(HCOOH) * M(HCOOH) = 0.200 L * 0.1 moles/L = 0.020 moles

Here, the limiting reagent is NaOH

The reaction is represented as:

HCOOH + NaOH ↔HCOONa + H2O

Moles of HCOONa formed = Moles of the limiting reagent, NaOH = 0.015 moles

Moles of HCOOH remaining = 0.020-0.015 = 0.005 moles

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Therefore: [HCOOH] = 0.005 moles/1 L = 0.005 M

[HCOONa] = 0.015/1 = 0.015 M

pKa of HCOOH = 3.74

As per Henderson-Hasselbalch equation

pH = pka + log[HCOONa]/[HCOOH] = 3.74+log[0.015/0.005] = 4.22

Therefore, pH of the final solution = 4.22


                       


3 0
3 years ago
Which aqueous solution has the lowest freezing point c6h12o6, c2h5oh, ch3cooh, or nacl?
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Depression of a freezing point of the solutions depends on the number of particles of the solute in the solution.
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