Basic questions...please help me...?

Question

Question 1:
A rock such as granite could be classified as a mixture because it:
a) consists of more than one type of atom
b) is a natural solid
c) may be broken down into separate compounds by physical processes
d) is homogeneous in composition
may be only separated into its constituent elements by chemical processes

Question 2:
Which of the following processes would be the most suitable for removing only undissolved solid impurities from a sample of sea water?
a) chromatography
b) distillation
c) evaporation
d) filtration
e) crystallisation

Question 3: Which of the following involve chemical changes and which involve only physical changes?
1-growth of a plant
2- kicking a football
3- magnetising a screwdriver
4- production of sound by the vocal cords
5- running a car engine
6-healing a wound

Thankyou! Please be certain about your answers and tell me why it is that. Thankyou.

For question 3 I need to say for each one which is a physical change and which is a chemical change. For ALL of them. Not just one.

Pleas just help me!

Answer 1

1 -- c) may be broken down into separate compounds by physical processes. The definition of a Mixture includes that it can usually be separated by mechanical means. Granite is a mixture of feldspars, quartz, hornblende, muscovite and/or micas.

2 -- d) filtration

3 -- Involve chemical changes:
....1-growth of a plant
....4- production of sound by the vocal cords
....5- running a car engine
....6-healing a wound
(The production of sound by the vocal cords requires muscles to contract, this is were the chemistry gets involved)

Only Physical changes:
....2- kicking a football
....3- magnetizing a screwdriver
(If you include the muscles involved in the kick or moving the magnet on the screwdriver, then these are also in the list above).

The use of muscles requires a complex series of chemical reactions. If the magnetizing a screwdriver was performed by a robotic device, then it would be the only thing listed which is only physical.

Answer 2

Pleas just help me!= Read an encyclopedia like I did in school !

Answer 3

uhh is this ur science homework????? i mean if it is.... uhh cant you just ask ur parents or something,,,but if u do really need help i ll help you :)

Answer 4

A
B
C
2