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2 years ago

Which of the following is an example of a physical change?

Chemistry

1 answer:

Pavel [41]2 years ago

3 0

Answer:

A. A solid dissolves.

Explanation:

The physical change from the given choices is that a solid dissolves.

The dissolution of a solute in a solvent is a physical change and not a chemical change.

A physical change has the following properties:

they are easily reversible
leads to the production of no new kinds of matter
involves no change in mass
requires little energy

You might be interested in

Is milk a solution, suspension, compound , colloid ?

kakasveta [241]

Answer:

Colloids (heterogeneous)

The difference between a colloid and a suspension is that the particles will not settle to the bottom over a period of time, they will stay suspended or float. An example of a colloid is milk. Milk is a mixture of liquid butterfat globules dispersed and suspended in water.

3 0

2 years ago

Scientists are studying animals in a large lake area. In this lake area, both owls and raccoons eat ducks, and ducks eat frogs.

Stolb23 [73]

Answer:

Population of duck and frog will change with the change

Explanation:

The complete question is

Scientists are studying animals in a large lake area. In this lake area, both owls and raccoons eat ducks, and ducks eat frogs. The data shows that recently the size of the raccoon population decreased. How will the decrease in the raccoon population affect the other populations? Be sure to explain whether the owl population, the duck population, and the frog population will change, and why.

Owl population will change
Duck population will change
Frog population will change

Solution

Raccoon eat duck and duck eat frog. Now if the population of Raccoon decreases then the number of predators of duck will decrease thereby increasing the population of duck.

The higher will be the number of ducks, the more frogs they will consume thereby decreasing the population of frogs

Hence both the population of duck and frog will change with the change

5 0

3 years ago

You take three compounds consisting of two elements and decompose them. To determine the relative masses of X, Y, and Z, you col

miss Akunina [59]

Answer:

a) LAW OF MULTIPLE PROPORTIONS

b) 0.095g, 0.71g, 0.285g respectively

c) X2Y, YZ15, X6Y

d) hence mass of compound X = 21 x 0.045 = 0.95g

mass of compound Y = 21 x 0.955 = 20.05g

Explanation:

a) The assumptions made in solving this questions is the application of the LAW OF MULTIPLE PROPORTIONS. The Law of multiple proportions states that if two elements A and B combine together to form more than one compound, then the several masses of A which chemically combine with a fixed mass of B is in a simple ratio.

for example, copper forms two oxides ; copper(I) oxide (CuO) and copper(ii) oxide(Cu2O), it is possible for the two samples of the oxides to be reduced to Cu by reacting with Hydrogen gas. as such, certain masses of oxygen combine separately with a fixed mass of Cu. then the ratios of Cu are then determined.

b) To calculate the relative masses, we take note of the three compounds given, they all have some amount of Y in them, hence we can use Y as our relative mass, this implies that the relative mass of Y = 1g

mass of X = 0.4g

mass of Y = 4.2g

amount of X in 1g of Y = 0.4 x 1 /4.2

= 0.095g

for compound 2;

mass of Y = 1.4g

mass of Z = 1.0g

amount of Z in 1g of Y =1.0 x 1 /1.4

= 0.71g

for compound 3;

mass of X = 2.0g

mass of Y = 7.0g

amount of X in 1g of Y = 1 x 2/7

= 0.285g

c) Applying the law of multiple proportions; since elements X and Z combine with a fixed mass of Y, they must bear a simple ratio;

compound 1/compound 3 = 0.095/0.285

= 1/3

compound 1/compound 2 = 0.095/0.71

= 2/15

compound 2/ compound 3 = 0.71/0.285

= 5/2

formular for compound 1 = X2Y

formula for compound 2 = YZ15

formular for compound 3 = X6Y

d) from the formular X2Y, we can get the amount of each product in XY using the ratios

%of compound XY in X = mass of compound X / total Mass

= 0.2/4.4 = 4.5%

as such in a 21g of compound XY, %of compound Y = 1 - %of compound X = 95.5%

hence mass of compound X = 21 x 0.045 = 0.95g

mass of compound Y = 21 x 0.955 = 20.05g

5 0

3 years ago

2567 milliliters to liters

andrew-mc [135]

Answer:

2.567 litres

Explanation:

I dont have a proper explanation sorry

6 0

2 years ago

Calculate the solubility of zn(oh)2(s) in 2.0 m naoh solution. (hint: you must take into account the formation of zn(oh)2−4, whi

Brilliant_brown [7]

When we have:

Zn(OH)2 → Zn2+ 2OH- with Ksp = 3 x 10 ^-16

and:

Zn2+ + 4OH- → Zn(OH)4 2- with Kf = 2 x 10^15

by mixing those equations together:

Zn(OH)2 + 2OH- → Zn(OH)4 2- with K = Kf *Ksp = 3 x 10^-16 * 2x10^15 =0.6

by using ICE table:

Zn(OH)2 + 2OH- → Zn(OH)4 2-

initial 2m 0

change -2X +X

Equ 2-2X X

when we assume that the solubility is X

and when K = [Zn(OH)4 2-] / [OH-]^2

0.6 = X / (2-2X)^2 by solving this equation for X

∴ X = 0.53 m

∴ the solubility of Zn(OH)2 = 0.53 M

4 0

3 years ago