Science Notes PDF

Unit 1 Part 3 - 14,35,27,28,29 Unit 1 Part 4 - 7,8,9,21,29,33 Unit 1 Part 5 - 10,11,12 Unit 2 Part 1 - 24,28,22,33 Exercise 1: Oxygen = 16 8O = K2 L6 since it has 6 valence electrons, it will gain 2 electrons to fill the octet rule so O-2 ( anion = negatively charged and gains electrons) Lithi...

Unit 1 Part 3 - 14,35,27,28,29 Unit 1 Part 4 - 7,8,9,21,29,33 Unit 1 Part 5 - 10,11,12 Unit 2 Part 1 - 24,28,22,33 Exercise 1: Oxygen = 16 8O = K2 L6 since it has 6 valence electrons, it will gain 2 electrons to fill the octet rule so O-2 ( anion = negatively charged and gains electrons) Lithium = 7 3Li = K2 L1 since it has 1 valence electron, it will lose 1 electron to fill the octet rule so Li+1 (cation = positively charged and loses electrons) Element Atomic Mass Number Number Charge Number Number of protons of electrons 40 20 Ca 2+ 20 40 20 18 +2 cation 35 17 Cl 1- 17 35 17 18 -1 ation 26 13 Al 3+ 13 26 13 10 +3 cation 16 8 O 8 16 8 8 0 its a neutral  atom Anion = Negative = Gain electrons Cation = Positive = Lose electrons Aluminum = 26 13 Al = K2 L8 M3 since it has 3 valence electrons, it will lose the 3 electrons to fill the octet rule Al+3 (cation = positively charged) Nitrogen = 14 7 N = K2 L5 since it has 5 valence electrons, it will gain 3 electrons to fill the octet rule (anion = negatively charged) What is the law of conservation of mass? The law of conservation states that the total quantity/amount of matter is neither created nor destroyed,it only changes its form (IMPORTANT) Example: A 3g piece of banana is cut into 3 pieces A-3g (banana)---> 1g+1.5g= 1.7g NO conservation of mass because mass before (3g) is not equal to the mass after (4.2g) B- 3g (banana)--> 1g+0.7+1.3g (sum - 3g ) There is a conservation of mass because the mass before ( 3g ) is equal to the mass after (3g ) What is the difference between physical and chemical change? GIVE EXAMPLES In physical change no new substances is formed the change is reversible and very little heat light energy is absorbed or given out during the reaction while in chemical change a new substance is formed the change is irreversible and a lot of heat or light energy is involved in the process Complete the table: Name of Compound First Element Second Element ( you add the “ide”) Hydrogen Chloride Hydrogen Chlorine Iron Nitride Iron Nitrogen Calcium Oxide Calcium Oxygen If you have a bar graph You have to interpret the graph before explaining the answer note:Sound travels the fastest in solid then liquid then gas According to the graph the speed of sound is the highest in medium X at 7000m/s. Then it decreases to 19000 m/s in medium Z and finally decreases to 500 m/s in medium. This indicates that medium x is solid because the speed of sound is the highest. Medium Y is a gas because the speed of sound is the lowest and medium Z is a liquid because the speed of sound is intermediate. Types of acid Time taken for hydrogen vegas to release Strong acid 40 Medium acid 25 Weak acid 10 INTERPRET the data in the table and to explain how the type and strength of acid affect the reaction time to hydrogen gas release By referring to the above table,the time taken for hydrogen gas to release when a metal is mixed with strong acid is 46 the time decreases to 25 secs with medium acid and decreases more to 10 secs with a weak acid. This indicated that the faster reaction happens with a strong acid