Chemistry

Theories

100

What is chemistry?

Chemistry is the study of matter and its changes.

200

What do we call vaporisation?

Liquid to gas.

300

What is homogeneous mixture?

If we cannot see what the mixture consists of then it will be homogeneous mixture.

400

What is an atom made of?

Nucleus and electrons.

500

What is formula?

A formula is a combination of symbols and numbers that represents compounds.

Calculate

100

What is the number of electrons and neutrons of a bromine ion?, if:

A=80

p=35

charge is=-1

Neutrons: 45

Electrons: 36

200

Write the electron configuration of In (Indium)?

In:[Kr]4d¹⁰5s²5p¹

300

What is the number of moles of 112L chlorine (Cl₂) gas at STP?

n=5mol.

400

Element X has 3 isotopes: ²⁰X-50%; ²¹X-25%; ¹⁹X-25%. What is the average atomic mass of X?

20

500

What is the number of moles of 3.01*10²² atoms of helium (He)? 

n=0.05mol

Name of ions

100

What is the formula of acetate anion?

CH₃COO

200

What is the formula of laughing gas?

N₂O - nitrous oxide

300

Br₂O₅

Dibromine pentoxide

400

Formula of silicon dioxide

SiO₂

500

PbCrO₄

Lead(ıı)chromate

Ractions

100

Complete the reaction and balance the equations:

HBr+H₂SO₄=

2HBr + H2SO4 = Br2 + SO2 + 2H2O

200

Two compounds are combined and switch partners

Double displacement

300

Cu+AgNO₃=

Cu+AgNO₃=CuNO₃+Ag

400

Cu(OH)₂+HC₂H₃O₂=

Cu(OH)₂+2HC₂H₃O₂=CuC₂H₃O₂+2H₂O

500

Silver nitrate + Zinc chloride -> Silver chloride + zinc nitrate

2AgNO₃+ZnCl₂=2AgCl+Zn(NO₃)₂

Others

100

Types of formulas

1. Empirical formula

2. Molecular formula

3. Structural formula

200

What is Isotope

Same protons different neutrons

300

Name the following compound:

Na₂CrO₄

Sodium chromate

400

What is Avogadro’s number and number of volume at STP?

Avogadro’s number: 6.02*10²³

^{Number of volume at STP: 22.4}

500

Who was D.I.Mendeleev?

He was a chemist who created the periodic table of elements.