What are the four important steps needed to obtain accurate meting points on a mel-temp?

a)grind the sample some.

b)grind the sample into a fine powder.

c)put the smallest amount you can see in a capillary tube.

d)fill the capillary tube with about 3mm of powder

e)set the voltage to rise quickly to 20 degree below the expected temperature, then re adjust so the temp rises at 2 degree per minute.

f)set the voltage to rise quickly to 20 degree below the expected temperature, then re adjust so the temp rises at 10 degree per minute.

g)record the temp at which liquid first appears and the temp at which the last crystal disappears.

h)record the temp at which the sample completely melts and the temp when it boils.

(b)

(d)

(e)

(g)

Explanation:

The four (4) important steps that are needed to obtain an accurate melting point is given as;

•First is Grinding: Grind the sample into fine powder.

•Second is Filling: Fill the capillary tube with about 3mm of powder

•Third is Adjusting the temperature: Set the voltage to rise quickly to 20° below the expected temperature, then re-adjust so the temperature rises at 2° per minute.

•Lastly is Observation and recordings: Record the temperature the temperature at which liquid first appears and the temperature at which the last crystal disappears.

I hope this helps, cheers.

- calcium has greater affinity to bond with electron receptors than hydrogen does and hence, it has the ability to replace hydrogen in most of its compounds.

- lithium has 2 valence electrons in the product because it can make only 1 bond with hydrogen. beryllium has 4 valence electrons in the product because it can only make 2 bonds. it has fewer electrons than neon and can react with electron donors. each hydrogen has 2 valence electrons, the same as helium.

- the covalent bond formed between carbon and hydrogen is polar because carbon is more electronegative than hydrogen and it attracts the bonded electron pair closer to itself, thus giving hydrogen a partial positive charge.

- a hydrogen bond is a relatively weak bond that hydrogen atoms make with the electronegative atoms nitrogen, oxygen or fluorine.

so the best choice is a.) 2 calcium (ca) atoms