All categories

3 years ago

Hello does anyone get this????????????? pls help

Chemistry

2 answers:

viva [34]3 years ago

7 0

Explanation:

physical changes : boiling water, freezing water, a pencil being sharpened.

chemical change : rotting cheese, exploding dynamite.

Leya [2.2K]3 years ago

7 0

Answer:

boiling water

a pencil being sharpened

freezing water

Explanation:

A change that does not lead to any difference in chemical composition of a substance is known as a physical change.

For example, shape, size, mass, volume, density, boiling point, etc of a substance are all physical properties.

On the other hand, changes that lead to bring change in chemical composition of a substance is known as a chemical change.

For example, exploding dynamite, rotting cheese etc are all chemical changes.

Chemical change is the change in which there is rearrangement of atoms and the new substances get formed.

Boiling water only changes the phase from liquid to gas and thus is a physical change.

Pencil on being sharpened only gets smaller in size and thus is a physical change.

exploding dynamite would result into formation of new substances and hence a chemical change.

Freezing water only changes the phase from liquid to solid and thus is a physical change.

Rotting cheese would result in formation of new substances and hence a chemical change.

Therefore, we can conclude that following are the physical changes in matter.

boiling water.

a pencil being sharpened.

freezing water.

You might be interested in

Which has a higher melting point and why? LiF or Rbl?

ExtremeBDS [4]

Explanation:

To get a better understanding of the answer,let's take use of Fajan's rule which says that no bond is neither purely covalent or purely ionic.

For ionic compounds MP and BP are higher than covalent compounds. So in order to find the one with higher MP,it's enough to find the most ionic compound among the given options.

In LiF,LiCl,LiBr and LiI,The cation is same and anion only differs.According to Fajans rule Smaller anion and larger cation favours ionic bonding and vice versa. Since Fluoride is the smallest anion,LiF is the most ionic compound and hence it is the one with highest MP from the options.Hope it helps

7 0

3 years ago

Identify the term that matches each definition.

Katen [24]

Answer:

Explanation:

The front vent of a fume hood that assists and maintain proper air circulation is Airfoil

The horizontal flat surface area of the fume hood where experiments are being carried out is Work Surface.

The main characteristics which demonstrate and describes how substances evaporate rapidly and readily into the thin air while producing a huge amount of vapor is known as Volatile

In front of the fume hood, lies the glass panel whose main purpose is to shield the user from the hazardous substance. This glass panel is known as the Sash.

6 0

3 years ago

Whats the difference between covalent and ionic bonds

il63 [147K]

Answer: The two main types of chemical bonds are ionic and covalent bonds. An ionic bond essentially donates an electron to the other atom participating in the bond, while electrons in a covalent bond are shared equally between the atoms. The only pure covalent bonds occur between identical atoms.Jan 23, 2020

Explanation: Hope this helped!!!!

4 0

3 years ago

Why doctors say to drink water

-BARSIC- [3]

Water is very healthy and beneficial, i some areas you may be told to drink plenty of fluids while sick (common cold) this can replace the fluids you've lost and loosen mucus, together with keeping you hydrated.

water is also helps in lubricating bone joints, moisturizing skin, detoxing your body, it can help with headaches , it balances body fluids

5 0

4 years ago

Read 2 more answers

Tell whether the following pairs of compounds are identical, constitutional isomers, stereoisomers, or unrelated. (a) cis-1,3-Di

Aleks04 [339]

Answer:

(a) Constitutional Isomers

(b) Constitutional Isomers

Explanation:

Constitutional isomers are also known with the name Structural Isomers. These are the compounds which have same chemical formula but differ in arrangement of atoms i.e. structure.

Both the compounds cis-1,3-dibromocyclohexane and trans-1,4-dibromocyclohexane have the same chemical formula $C_{6} H_{10} Br_{2}$ but have different structure as shown in the image below.

In the second case the compounds 2,3-dimethylhexane and 2,3,3-trimethylpentane, both have same chemical formula $C_{8} H_{18}$ but have different structures which is shown in the image below.

Thus it is clear that in both the groups (a) and (b) the given compounds are Constitutional Isomers.

7 0

3 years ago