Experiment chemistry (chap1)
What do pure substances have?
Fixed boiling and melting points
Explain the packing of particles in liquid
Packed closely together but not as tightly as solids. No regular arrangement
Define an atom
An atom is the smallest particles that can still have the chemical characteristics an element
Define a compound
Made up of two or more atoms of the same element
Name 3 alloys
Bronze brass solder rose gold, purple gold, steel, stainless steel
What does a pipette measure?
Accurate fixed volumes, 10.0cm or 25.0cm
Define kinetic particle theory
All matter is made up of particles which are in constant random motion
What is the relative mass and relative charge of a Proton, neutron and electron?
1,1,1/1840
+1,0,-1
Define what a positive ion is
They have more protons than electrons and have a positive net charge
Define a simple covalent substance
Gases or liquids at room temperature and pressure
Which method of collecting gases can gas be soluble?
Downward and upward
What happens when an object is heated?
Thermal energy is transferred to its particles. Some of this energy is converted to kinetic energy of the particles
Define an isotope
Atoms of the same element that have the same Proton (atomic) number but different nucleon(mass) numbers. Meaning they have different numbers of neutrons
Substance X has the following properties.
It conducts electricity when molten.
It has a high melting point.
It dissolves in water.
What is X likely to be?
A copper
B silver chloride
C sodium chloride
D hydrogen chloride
B
Why can metals that are made up of layers of atoms can slide over one another?
Metals are malleable
What is the use definition of fractional distillation?
Used to seperate miscible liquids with different boiling points
Describe what happens to the particles of a mixture when it condenses
The particles lose energy to the surrounding, with less energy the particles are drawn closer together by the forces of attraction between them. The arrangement of the particles during the condensation process.
What is the chemical formulae for Copper(ii) sulfate?
CuSO4
Name all Noble gases
Helium, neon, argon, kryption, xenon, radon and oganesson
Define relative atomic mass number, Ar
Average mass of an atom of the element relative to 1/12 of the mass of an atom of carbon 12
Gas X is soluble in water. Its solution turns red litmus paper blue. Which statement is not correct?
A A green precipitate is obtained when an aqueous solution of X is added one drop at a time to aqueous iron(III) nitrate.
B A white precipitate is produced, which then dissolves when an aqueous solution of X is added one drop at a time to aqueous zinc nitrate.
C Gas X could be made by warming ammonium nitrate with aqueous sodium hydroxide.
D Gas X could be made by warming calcium nitrate with aqueous sodium hydroxide and
A, gas X is most likely to be ammonia a basic has that is soluble is water
When ammonia is added to IronIII nitrate, a reddish brown presipitaye is obtained instead of a green precipitate
Explain in terms of kinetic particle theory: you can smell the aroma of freshly brewed coffee across the room
Kinetic particle theory states that particles in all states of matter are constantly moving. In gases, particles move randomly and at high speeds, filling the space they occupy. The coffee aromas gas particles then mix with the air particles around them. + diffusion
3. According to the theory, gas particles move quickly in all directions. As the coffee's volatile molecules are released, they collide with air particles, causing them to spread out and disperse throughout the room.
4. As a result of this random motion and collisions, these gas molecules gradually spread across the room, reaching your nose, allowing you to detect the smell.
Explain, with reference to its structure, why the use of steel is preferred over pure iron when used to construct buildings
The additional different size atoms to iorn will disrupt it's regular arrangement and makes it harder for the layers of atoms to slide pass one another
With reference to an oxygen atom bonding and structure, explain why it has low melting and boiling points
It has a simple molecular structure where little energy is required to overcome the weak molecular forces between molecules Hence it has a low melting point and boiling point
The chemical equation for the reaction between nitric acid and potassium carbonate is as follows:
2HNO3+K2CO3 -> 2KNO3+CO2+H2O
50.0CM3of 0.500 mol/dm3nitric acid is added to an aqueous solution of potassium carbonate.
Calculate the colume of carbon dioxide formed
Ratio of HNO3:CO2
2:1
0.025:0.0125
VOL=0.0125x24=0.3dm3