Chemistry questions?

Question

A) Divide the following into elements or compounds: O2, H2, H2O, Ar, CO2, CH4, C6H12O6.

B) The formula for ethanol is C2H5OH
i. How many types of atoms are there?
ii. How many atoms are there in total?
iii. What do the symbols C, H and O stand for?

C) How many atoms of each type are present in the following molecules:
i.NH3
ii. CH4
iii. CaCO3
iv. NaOH
v. Fe(OH)3
vi. KSCN

Answer 1

A)
Elements: O2, H2, Ar (only one type of atom)
Compounds: H2O, CO2, CH4, C6H12O6.

B)
i/iii: Three types of atoms: C (Carbon), H (Hydrogen), O (Oxygen).
ii: 2+5+1+1 = 9 atoms in each molecule of ethanol.

C)
i. One nitrogen atom, three yydrogen atoms.
ii. One carbon, four hydrogen
iii. One calcium, one carbon, three oxygen
iv. One sodium, one oxygen, one hydrogen
v. One iron, three oxygen, three hydrogen
vi. One potassium, one sulphur, one carbon, one nitrogen.

Note with C(v) that the (OH)3 means that the 3 applies to both the O and the H, whereas OH3 would mean one O and three H.

Answer 2

A) elements : Ar
compunds : O2, H2, H2O, CO2, CH4, C6H12O6

B
(i) 3 types
(ii) 9 atoms
(iii) C = Carbon, H= Hydrogen, O=Oxygent

C) How many atoms of each type are present in the following molecules:
i.NH3 = 3H and 1 N
ii. CH4 = 4 H and 1 C
iii. CaCO3 = 1 Ca, 1 C and 3O
iv. NaOH = 1 Na, 1 O and 1 H
v. Fe(OH)3 = 1 Fe, 3 H and 3O
vi. KSCN = 1 K, 1S, 1C and 1N

Answer 3

1. From a side view of a book, you will notice that there is two sides of the cover and pages. This means that the thickness should be: Thickness = 200 * page length + 2 * cover length = (200*0.10mm)+(2*0.020mm) = 20.04 mm = 2.004 cm 2. Volume = length * width * height = 10cmx2cmx2xm = 40 cm^3 A 2cmx2cmx2cm block is of volume 8 cm^3. If you take the total volume of the metal block and divide it by the volume of each individual block, you should find how many blocks you need: 40 cm^3/8cm^3 = 5 blocks Chemistry questions: - Evaporation is the actual process of taking a substance and converting is from liquid phase to gas phase. Boiling is the point where the pressure exerted by the liquid matches the surrounding pressure, thus causing the substance to begin evaporating. - The higher pressure you have, the tighter the air is packed, and the more the energy of the molecules is contained and conserved. The energy of the molecules, at our level is indicative of heat. Thus, the more pressure exists, the hotter the contained product becomes... which allows for faster and easier cooking (since you are able to hold onto more heat for a longer period of time).

Answer 4

B)
types of atoms:C,H,OH
3 ATOMS IN TOTAL
C is carbon,H = hydrogen,O= oxygen