What gas is produced when calcium metal is dropped in water

1 answer:

3 0

Hydrogen gas

Calcium + Water. In the following demonstration, a chunk of calcium metal is dropped into a beaker of distilled water. After a second or so, the calcium metal begins to bubble vigorously as it reacts with the water, producing hydrogen gas, and a cloudy white precipitate of calcium hydroxide.

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Ice floats on water. For most other substances, however, the solid sinks in the liquid. Classify each of these statements based

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Answer:

1.High pressure will cause the liquid to become solid :

Describe both water and other substances

2.High pressure will cause the solid to become liquid :

It describe none : neither water nor other substances 

This statement is :False for both water and other substances

3.The solid is more dense than the liquid :

It describe other substance

This statement is :False for water but true for other substances.

4. In a phase diagram, the solid-liquid coexistence line has a negative slope.

It describes water:

This statement is :True for water because solid ice is less dense than liquid water.

False for other substance, they have positive slope

5.The molecules are closest in the liquid phase.

This statement is :False for water and other substances

6.The solid is less dense than the liquid:

It Describes water because ice is less dense than liquid water

7. In a phase diagram, the solid-liquid coexistence line has a positive slope.

It describe other substances

This statement is :True for other substances but false for water

8. The molecules are closest in the solid phase :

Describes both water and other substances

Explanation:

Answers to statement 1 , 2,5 and 8

Answers to statement 1 , 2

On increasing pressure and decreasing temperature , There occur Phase transition always for every substance :

From liquid to solid and gas to liquid

Hence,

In Both for water and other substance

High pressure will cause the liquid to become solid.

Answers to statement 5,8 :

2.The Particles of solid are closely packed hence there is maximum force of attraction between the particle of solid as compared to liquid and gases .

Hence , The molecules of both water and other substances are closest in the solid phase

This also means that in liquid molecules are far apart .

Rest statement : 3, 4 ,6 ,7 are explained below(see attached image)

The molecules are closest in the liquid phase is false statement and does not describe both water and other substance

Ice floats on water. For most other substances, however, the solid sinks in the liquid.

This can be explained using the phase diagram of water :

The line DB is = the solid-liquid coexistence line

It has negative slope because , solid ice is less dense than liquid water . That is why ice floats on water because its density is less than water

Hence Water is described truly by statement 4,6, which are :

4. the solid-liquid coexistence line has a negative slope.

6.The solid is less dense than the liquid.

Rest 3,7 = describe by other substance