Chapter 3: Atoms and Molecules

a. Diatomic (2 atoms)

b. Triatomic (3 atoms)

c. Triatomic (3 atoms)

d. Polyatomic (8 atoms)

e. Polyatomic (4 atoms)

f. Polyatomic (4 atoms)

g. Polyatomic (14 atoms)

h. Triatomic (3 atoms)

i. Diatomic (2 atoms)

j. Polyatomic (5 atoms)

k. Monoatomic (1 atom)

l. Monoatomic (1 atom)

Heating:

Upon heating sugar melts to liquid form because sucrose has a decomposition point and melting point at temperatures between 190 to 192 degrees Celsius. This will turn sugar to light brown colour. On heating further, sugar gets charred to black colour.

Salt has a melting point of 841 degrees Celsius and 1545.8 degrees Fahrenheit. If we don’t heat it to that point no change is observed.

Electrical conductivity:

If we dissolve the given substance in water we can check for electrical conductivity to check whether the substance is sugar or salt. If it is salt it conducts electricity. Because salt (NaCl) has positive sodium ions and negative chloride ions hence salt conducts electricity. But sugar doesn’t conduct electricity as sugar has only positive ions.

Number of moles = weight atomic weight

= 12/24 = 0.5 moles