Hi, I'm new so please be nice but im desperately in need of help!

Right, I'm not actually thick lol, but this first section of the AS course is killing me after just the 1st week!

1)How many moles of sugar in 1kG of sugar? *c12-h22-o11* Well I got (1000/342g) = 2.92 moles, not sure if its right.

Now how do I work out the number ofmoleculesof sugar in 1Kg?

*if the relative molec mass is 342*

2)How many moles of water *18* in 90g of water? - I got (90/18 ) = 5

Then it asks, how many molecules is that? - This is where I get quite confused, could somebody please explain?

It also asks, how many atoms are present in that amount? - I tried 5xAvogadro's constant. Is this how it is done?

3)The mass of one molecule of a compound is 7.33 x 10^ -23. Calculate its relative molecular mass. *Confuseddd.com*

4)Calculate the mass of 50 litres of methane (ch4) at STP.

No clue and it's doing my head in.

I have just started a new sixth form at a selective school and have been placed in the top chemistry set based on my gcse grade, reference and aptitude test score. Sadly I feel well out of my depth so if somebody could please explain this to me, it would really help me regain my confidence and would be much appreciated!