About

“We must trust to nothing but facts: These are presented to us by Nature, and cannot deceive. We ought, in every instance, to submit our reasoning to the test of experiment, and never to search for truth but by the natural road of experiment and observation.” ― Antoine Lavoisier, Elements of Chemistry

Categories

Popular Posts

c h e m i s t r y 4 u s

The science of today is the technology of tomorrow, Edward Teller

c h e m i s t r y 4 u s

Success is no accident. It is hard work, perseverance, learning, studying, sacrifice and most of all, love of what you are doing or learning to do. Pele

c h e m i s t r y 4 u s

Optimism is the faith that leads to achievement. Nothing can be done without hope and confidence. Helen Keller

c h e m i s t r y 4 u s

Science without religion is lame, religion without science is blind. Albert Einstein

c h e m i s t r y 4 u s

Insanity: doing the same thing over and over again and expecting different results. Albert Einstein

Wednesday, 25 September 2013

Pattern of Reactivity Quiz

REACTIVITY SERIES - Chem is try  2
Workout these questions with your learning partner. There are 40 marks possibly.


1)      Answer the following questions in full sentences.
a)     Why does gold occur native (uncombined) whereas zinc does not?
………………………………………………………………………………………………
b)     Why was silver used to make coins in the past?
………………………………………………………………………………………………
c)      Why is copper used to make electrical cables and wires?
………………………………………………………………………………………………
 (3)
  2)      The following metals are listed in order of reactivity (most reactive first)
sodium  >  magnesium  >  zinc  >  copper
a)     Describe what each metal does when
(i)    heated in air  …………………………………………………………..
(ii)  added to dilute hydrochloric acid……………………………………..
b)     Which of the four metals would be suitable for making saucepans?  Explain why the others are not.
………………………………………………………………………………………………
………………………………………………………………………………………………
(5)

3)     Describe what you would see if you dropped a piece of magnesium ribbon into some copper sulphate solution in a test tube.  Write a word equation for the reaction.
………………………………………………………………………………………………
……………………………………………………………………………………………...
………………………………………………………………………………………………
………………………………………………………………………………………………
(3)

4)     Complete the following word equations.
a)     zinc   +   lead nitrate solution  ………………………………………………………….
b)     iron   +   zinc sulphate solution  ………………………………………………………..
c)      lead   +   copper nitrate solution ………………………………………………………
d)     magnesium   +   zinc chloride solution  ………………………………………………..
e)     copper   +   sodium chloride solution  …………………………………………………
f)       zinc   +   iron sulphate solution  ………………………………………………………..
g)     gold   +   silver nitrate solution  ………………………………………………………..
h)     magnesium   +  calcium nitrate solution  ……………………………………………..
(8)
5)     Three metals X, Y and Z have the following reactions:-
Y will displace X from a solution of its salt.
Z will displace both X and Y from solutions of their salts.
Place the three metals in order of reactivity, starting with the least reactive.
………………………………………………………………………………………………
(2)

6)     Here is a list of metals in order of decreasing reactivity.  Q and R are mystery metals.
K > Q > Ca > Mg > Al > Zn > R > Fe > Cu
a)     Will Q react with cold water?                                                              …………
b)     Will R react with cold water?                                                                              …………
c)      Will R react with dilute hydrochloric acid?                                 ...……….
d)     Will R displace copper from copper sulphate solution?    ...……….
e)     Write word equations for any reactions in parts a) to d)
………………………………………………………………………………………………….
………………………………………………………………………………………………….
………………………………………………………………………………………………….
………………………………………………………………………………………………….
(6)
7)     Describe everything you see when sodium is added to water containing universal indicator.

Name the two chemical products of sodium reacting with water and give the symbol equation for the reaction of sodium with water.
(3)
8)     (a) Give two observations that could be made after adding zinc to copper(II) sulphate solution.

(b) Give the symbol equation for the reaction between zinc and copper(II) sulphate solution.

(4)
(c) explain why this is an example of a displacement reaction.

  9   (a) Give three observations that could be made when magnesium reacts with sulphuric acid.
     (b) Give the word and symbol equation for zinc reacting with sulphuric acid.
     (c) From copper, iron, magnesium and zinc: Which reacts with acid (i) fastest?, (ii)slowest?
(6)


Tuesday, 24 September 2013

alkane alkene worksheet

WORKSHEETS
Worksheet 1 : Carbon Compound
1. Carbon compounds are compounds which contain ………………
2.Hydrocarbons are the simplest organic compounds containing …………….. and  …………….atoms  only. Some organic compounds  also contain other element such as oxygen, nitrogen and halogens ; the compounds are called ………………….
3.Saturated hydrocarbons contain entirely of carbon-carbon ……………….. bonds. Unsaturated hydrocarbons contain at least one carbon-carbon ……………… bond or carbon-carbon triple bonds.
4.The molecular formula is a chemical formula that shows the…………………………. of each element present in one molecule of the substance.
5.The structural formula  of an organic compound is the formula that shows  the ……………………………….. and the covalent bonds between atom in a molecule of the compound.
6.A ……………………series is a family of organic compounds with each member of the family differing from the previous member by having one more group of atoms
            –CH2 .  All members in the same family have the same  functional group and with
            similar …………………… properties.
7.A functional group is an atom or a group of atoms that determine the ……........ properties of an organic compound.
8 ……………………. are compounds which have the same molecular formula but
            different structural formula. The phenomenon whereby two or more molecules have the
            similar molecular formula but different structural formula is called ………………

As Level Chemistry-chemical equilibrium

Worksheet A            Equilibrium Calculations
            Solve each problem and show all of your work.
1.         SO3(g)         +     H2O(g)                ⇄    H2SO4(l)        
            At equilibrium [SO3] = 0.400M             [H2O] = 0.480M                  [H2SO4] = 0.600M            
            Calculate the value of the equilibrium constant.
 2.         At equilibrium at 100oC, a 2.0L flask contains:
            0.075 mol of PCl5             0.050 mol of H2O               0.750 mol 0f HCl           0.500 mol of POCl3
            Calculate the Keq for the reaction:
            PCl5 (s) + H2O (g) ⇄ 2HCl (g) + POCl3 (g)
3.         Keq= 798 at 25oC for the reaction:  2SO2 (g)   +  O2 (g) ⇄  2SO3 (g).
            In a particular mixture at equilibrium, [SO2]= 4.20 M and [SO3]=11.0M. Calculate the equilibrium [O2] in this mixture at 25oC.
4.         Consider the following equilibrium:
            2SO2 (g) + O2 (g) ⇄ 2SO3 (g)
            0.600 moles of SO2 and 0.600 moles of O2 are present in a 4.00 L flask at equilibrium at 100oC. If the Keq = 680, calculate the SO3 concentration at 100oC.
5.         Consider the following equilibrium:
            2 NO2(g)           ⇄        N2O4(g)
            2.00 moles of NO2 and1.60 moles of N2O4 are present in a 4.00 L flask at equilibrium at 20oC. Calculate the Keq at 20oC .
6.         2 SO3(g)           ⇄        2 SO2(g)           +          O2(g)
            4.00 moles of SO2 and 5.00 moles O2 are present in a 2.00 L container at 100oC and are at equilibrium. Calculate the equilibrium concentration    of SO3 and the number of moles SO3 present if the Keq = 1.47  x  10-3.
7.         If  at equilibrium [H2] = 0.200M and [I2] = 0.200M and Keq=55.6 at 250oC, calculate the equilibrium concentration of HI.
            H2 (g) + I2 (g) ⇄ 2HI (g)
8.         1.60 moles CO, 1.60 moles H2O, 4.00 moles CO2, 4.00moles H2 are found in a 8.00L container at 690oC at equilibrium.
            CO (g) + H2O (g) ⇄ CO2 (g) + H2 (g)
            Calculate the value of the equilibrium constant.

Wednesday, 18 September 2013

REACTIVITY SERIES worksheet

Workout these questions below.


Name                   : ______________________________              Marks   :
Date                      : ______________________________
 



1.    Katie and Nando have identical new bicycle. Katie lives in a dry, cool, grassland area and Nando lives in warm, wet region on the coast. Which bicycle may show signs of rusting first? Explain your answer.

2.    What is the relationship between rusting of metals and their reactivity?

3.    Iron, Aluminum, Lead, Copper, Tin, Zinc, Magnesium. Which of these element will rust first and which is the last?

Arrange the elements according to the reactivity. (most reactive to less reactive)

4.    Suggest the statement below:
a.         The roof of the house are potassium plate
b.         We can protect the fence in the yard by painting