Review exercises 2 ESO

• Balance these chemical equations:

1. Co + O2 => Co2O3
2. C4H8 + O2 =>  CO2 +  H2O
3. Fe + HCl =>  FeCl2 +  H2
4. Na + H2O => Na2O + H2

• Determine wheter these are chemical or physical:

1. Melting of ice
2. Oxidation of a wet screw
3. Solving salt into water
4. Drilling a wall
5. Photosynthesis

• Imagine this reaction of a fuel: CnH2n + O2 => CO2 + H2O. Tell if these factors will affect the reaction rate

1. The fuel is cooled to solid state
2. The fuel is vaporised
3. We control the temoperature reaction to 30ºC. 
4. We let the reaction temperature reach 1500ºC

• Tell if these proccess is biological or industrial:

1. Synthesis of a polymer
2. Human breathing
3. Mythosis
4. Cracking of oil

• Are these statements true or false. Tell why

1. The combustion of fuels affects the ozone layer.
2. CFCs provoque the ozone-s layer depletion
3. Global warming is only provoqued by the industrial activity
4. Atmospheric polution only provoques global warming
5. Soil polution has to do with waste dumping.
6. Only industries pollute water

Chemistry and the environment

Watch this video and answer:

What is the main cause for global warming?
Why does it affect climate?
What climatic effects  can it cause?
How does it affect ecosystems. Tell examples 
Why can it cause floodings?
What happens when CO2 solves into water?

Video 2:

What does this video tell us about?
Batteries?
Drinking?
Burning plastics?
Plastic foams?
Appliances?

Chemical reactions 2ESO

Watch these videos and answer the questions 

Video 1

• What is a chemical proccess
• What examples of chemical reactions do they give us?
• What type of properties change during a chemical reaction. Give examples of each type
• Explain, using the film's words, what a chemical equation stands for

Video 2:

Watch and apply to balance these equations:

• N2 + O2 -> N2O5
• CH4 + O2 -> CO2 + H2O
• Li + O2 -> Li2O

Exercises 3ESO stoichiometry

1. To obtain Alluminum, we ge reduce Alluminium  (III) oxide with graphite(C) to give Alluminium and Carbon dioxide. Write the chemical equation and tell how much Alluminium (in mass) we will get from a Kg of Alluminium  (III) oxide and how much CO2 will be produced.
   
2. The engine of a car burns 1kg fuel to run 20km. The formula of fuel is C8H16. If it reacts with oxigen to yield CO2 and water. Write the chemical equation of the proccess. Work out the mass of CO2 and water which is produced and the volume of O2 which is burnt. 

Review 4 ESO Organic Chemistry

Write the formula of 

1. 2 ethyl 3 hidroxi 4 cyclopentenone 
2. 2 methyl 4 hidroxi 3 hexynoic acid 
3. 2 propyl 5 ethyl 3 hexanodiol
4. 2,4 ciclopentenodiol

Name

An organic branched compound with terminal C=O bonds has a Pm=86g/mol. It has 7% of H and a 55,8%C. Determine its empiric and mollecular formula. Draw its geometric fórmula or its s.d. formula. 

Formulation Practise

Write the formula of:

¨

¨Lithium nitride

¨Berylium hydroxide

¨Hydrogen

¨Lead dioxide

¨Tin tetrafluride

¨Calcium hydride

¨Gold (III) oxide

¨Rubidium selenide

¨Sulphur (IV) oxide

¨Silver

¨Alumnium oxide

Name

¨K2O

¨Cl2

¨NiBr3

¨Co

¨Fe(OH)2

¨CaH2

¨NiN

¨Cu2O

¨SeF6

¨BaO

¨Mg(OH)2

Organic Chemistry Rewiew Weekend

• Name:

• Write the formula of 

a) 1,3,4 hexanotriol

b) 2 ethyl 5,5 dimethyl 1,3 hexadiene

c) 1,3 hexadien 5 yne

d) 2,5 diethyl 6 fluoro 3 hexynoic acid

• An organic dicarboxilic acid has a mollecular weight of 116 g/mol. It contains a 3.4%H and a 41,4%C. Determine its empiric and mollecular formula.  Draw its geometric/ semideveloped formula.

Quantities of chemical Species

When we study stoichiometry we have to calculate the quantities of Species in several ways:

Take the reaction:

 2HCl + Fe -> FeCl2 + H2

As you can appreciate, it is already balanced 
We now have to study the quantities of species. Stoichiometry is all about this. There are up to 4 magnitudes related to the quantity of substance:

• Mass(m): the basic amount of substance. We measure mass in g. We can use mass to express the quantity of a solid, a gas, or a liquid, but we shouldn't use it in a  chemical equation

• Volume, V: is used for gasses. A mole of gas in normal conditions fills 22,4L.

• Number of moles,n: which is the magnitude we handle in a chemical equation. A mole is a group which contains 600000 trillion!!!! particles. This is Avogadros number. Stoichiometric quotients refer to the number of moles

• Concentration, C. for solutions. It is the number of moles in a volume of 1L. The units are mol/L 2mol/L=2M

Now: How do we change from a magnitude to other???????: We have to use these fórmula

• From mass m to number of moles. We use the formula n=m/Pm. Pm is the mollecular mass: sum of the masses of all the atoms (Periodic table) of the compound. For instance, for HCl; Pm=1+35.5=36,5g/mol If we have 56g of HCl: n=m/Pm=56/35,5=1.58mol. If we have 2 mol of HCl, its mass will be m=n·Pm=2*36.5=73g
• From volume in a gas to number of moles: n=V/22.4L. 10L of H2 contain n=10/22.4L=0.45 moles. 2.5 moles of H2 fill V=22.4×n=22.4×2.5=56L. Then, to calculate Volume of a certain number of moles of a gas: V=22.4·n; 3 moles of H2 fill: V=22.4*3=67.2L 

• From concentration C and volume V of a disolution to number of moles n=CV. 2L of a 0.5M disolution have n=CV=0.5×2=1mol. 4 moles of a 2M substance fill V=n÷C=4÷2=2L

Now do these exercises in a piece of paper: You will need a PT


1. Calculate the mollecular mass of FeCl2, H2, AlCl3


2. Calculate the number of moles in 25g FeCl2, 4g H2, 80g AlCl3.


3. Determine the mass in 2.5 moles of FeCl2, 0.7 moles of HCL, 6 moles of H2O


4. Determine the volume of 0.3 mol of H2, of 1.5 mol H2 and 3.2 mol of H2. Determine the number of moles in 11.2L of H2 and 20L of H2. Determine the mass of 25L of H2


5. Determine the number of a)moles of 2L of HCl 2M. b) 500 mL of HCl 0.3 M How much mass of HCl would this solution contain (you must determine the number of moles of HCl first)


6. How much volume of HCL 0.6 M do we need to get a)0.3mol b)1.8 mol