Elements
Aluminium is an element characterized by being shiny, and can be hammered into sheets
Metals
Write the chemical formulae of:
Water:
H2O
Use the periodic table to know the symbol of Iron
Fe
Changing of state from solid to liquid is called _________
Melting
Non metals
Write the chemical formulae of:
Baking soda:
NaHCO3
Use the periodic table to know the atomic number of nitrogen
7
Blow up a beach ball or balloon.
Measure the air temperature.
Observe clouds forming.
Weigh a glass before and after it is filled with water.
Blow up a beach ball or balloon.
Is there any similarity between Evaporation and boiling? Explain.
Both are types of vaporization and they are changing from liquid to gas, both are endothermic.
List the three categories of elements
metals
non -metals
metalloids
Classify each of the following substances into elements or compounds.
Water, iron, salt, iodine, copper, lead and carbon dioxide
Elements: Iron, iodine, copper, lead
Compounds: Water, salt and carbon dioxide
Kinetic energy
Heat is absorbed, Sublimation , Endothermic
Metalloids are widely used in electronics in mobiles and computers industries. Explain why giving examples on metalloids.
They are semiconductors that conduct the right amount of electric current.
Sodium metal reacts with chlorine gas to produce sodium chloride which is the table salt we use. Are the properties of sodium chloride like those of the elements that made it? Answer by yes or no and explain your answer.
No, Because sodium and chlorine are poisonous and when they react they are chemically bonded to give new substance with new properties.
State the number of elements in each given compound ,then determine the number of atoms of each element : C₆H₁₂O₆
Carbon, Hydrogen, oxygen
3 elements
C=6
H=12
O=6
T=6+12+6=24 atoms
Does steam have definite shape or definite volume ?
Indefinite shape and volume
As you breathe on a mirror, a film of water briefly forms on the mirror. Is thermal energy released or absorbed? What kind of change of state is involved here?
Heat is lost ,Condensation ,Exothermic reaction
Compare between metals nonmetals and metalloids:2 points
Metals are shiny, Nonmetals are dull , Metalloids: some are shiny some are dull.
Metals are good conductors, of heat and electricity.
Non-metals are insulators
Metalloids are semi conductors
Compare between elements and compounds , 2points
Element : represented with chemical symbol while compound is represented with chemical formula
Elements can't be divided but compound can be divided into simpler substances by chemical means
State the number of elements in each given compound ,then determine the number of atoms of each element : Ca(OH) ₂
Calcium, oxygen, hydrogen
3 elements
Ca=1
O=2
H =2
T=1+2+2=5 atoms
A group of engineers needs to transport a large amount of oxygen, but they have only one truck. Explain which state of matter you would recommend the oxygen be in the transport. Explain why.
Solid because it will occupy the least space.
On a sunny day, a cold drink was left in the sun heat. Explain what will happen to the liquid particles as temperature increases (indicating what will happen to Kinetic energy, Speed of particles and distance between particles)
The particles will gain kinetic energy, they will start to move faster ,they will push each other apart breaking the bonds between them and the spaces will grow bigger.