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Harman [31]
3 years ago
12

Which of the following is an irreversible physical change?

Chemistry
1 answer:
Yuliya22 [10]3 years ago
3 0

Answer:

b) sharpening a pencil

Explanation:

If you melt lead, boil water, or dissolve sugar in water, you can return all of them back to their original state. If you sharpen a pencil, you can't reattach the shavings as they were originally.

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For which of the following aqueous solutions would one expect to have the largest van’t Hoff factor (i)? a. 0.050 m NaCl b. 0.50
ira [324]

Answer:

The van't hoff factor of 0.500m K₂SO₄ will be highest.

Explanation:

Van't Hoff factor was introduced for better understanding of colligative property of a solution.

By definition it is the ratio of actual number of particles or ions or associated molecules formed when a solute is dissolved to the number of particles expected from the mass dissolved.

a) For NaCl the van't Hoff factor is 2

b) For K₂SO₄ the van't Hoff factor is 3 [it will dissociate to give three ions one sulfate ion and two potassium ions]

Out of 0.500m and 0.050m K₂SO₄, the van't hoff factor of 0.500m K₂SO₄ will be more.

c) The van't Hoff factor for glucose is one as it is a non electrolyte and will not dissociate.

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3 years ago
Unequal heating of Earth's surface over a SMALL area causes ..??? (please answer fast)
ra1l [238]
Global win I think brace it say around small areas
5 0
2 years ago
a mineral that has - can be split fairly easily along plains with weak atomic attraction A. streak B. Cleavage C. luster D. Hard
tatyana61 [14]
I am going to have to say C. luster if not then B. Cleavage
5 0
3 years ago
Read 2 more answers
What are 2 ways microscopes have changed and improved from the 16th century to present day?
Ivan

Answer:

Glass and lens making have improved, and electronic features for microscopes have become available

Explanation:

5 0
2 years ago
Match the words to the definitions below.
puteri [66]

Answer:

Explanation:

1. Turns litmus paper blue, taste bitter, donate OH- ions, feel slippery, 8-14 on pH scale.

BASE

BASE: A base is a substance that reacts with water to yield excess hydroxide ions.

Some of its characteristics are:

>It has a bitter taste

>Their aqeuos solutions have a soapy feel

>They have a PH greater than 7

>They turn red litmus paper blue

>They are electrolytes

2. The amount of ions per an amount of solvent. Ex: 10g salt/100g water

CONCENTRATION

Concentration is the amount of solute that can be found in a solution.

3. A lab procedure to deliver a measured volume of solution, generally measured in ml.

TITRATION

Titration is a laboratory procedure that is used to determine the amount of solution that is needed to drive a reaction to completion. It involves adding a solution to a known volume of another solution.

4. A substance or solution that resists changes in pH by stabilizing hydrogen ion concentration.

BUFFER

A buffer is solution that is made up of weak acids and their salts or weak bases and their salts. Such solutions are able to resist changes in PH

5. Turns litmus paper red, taste sour, donate H+, corrode metals, 0-6 on pH scale.

ACID

An acid is a proton donor, hydrogen ions.

Characteristics:

>Acids turns blue litmus paper red, they have sour taste and easily corrodes metals.

>They have a PH value between 0-6 on the scale.

>They are generally electrolytes

6. Logarithmic scale to indicate the amount of hydrogen ions in solution.

PH SCALE

A PH scale is a logarithmic scale that runs from 1-14 and is used to indicate the amount of hydrogen ions in a solution.

7. A chemical (dye created from lichens) that changes color in response to changes in pH.

LITMUS PAPER

Litmus paper is made of dyes created from lichen and it changes its color as PH changes. Acids turns blue litmus paper red while bases changes the color of litmus to blue from red. Litmus test is a popular test for solutions.

8. Acids and bases are added proportionally and result in a chemical reaction that causes the pH of a solution to reach pH 7.

NEUTRALIZATION

Neutralization is the reaction of acids and bases to produce salts and water. The endpoint of neutralization reaction signifies the point at which equal number of bases neutralizes an acid. The PH is 7 at this point.

5 0
3 years ago
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