# Help with beginner chem stuff

1. Sep 14, 2004

### starsun

i have this chem teacher who does NOT teach from the book at all! he just expects us to read the book and understand it completely. so yeah i have a few questions that i cant do!

how long would it take a plane, traveling at an average speed of 634km/h, to cover a distance of 3912 km?

Determine the mass in grams of a hamburger that weighs 8.0 oz.

thanks!

2. Sep 14, 2004

### recon

Your first question is not a chemistry question. Your second question has little to do with chemistry.

You should know that Time = Distance/Speed.

You should also know that 1 oz. = 28.35 g.

3. Sep 15, 2004

### BobG

The first chapter is usually on non-chemistry basics, such as unit conversions, significant digits, etc.

Yes, speed = distance/time ..... or you can rearrange the equation to find either of the other two missing variables.

You should have a chart (either in one of the appendices or on a handout) that shows conversions from metric to english or english to metric. You use the dimensional analysis to eventually arrive at the proper units.

For example: to go from meters/second to miles/hour you have to multiply by (1 mile/1609 meters) and by (3600 seconds/1 hour).

The conversion can be flipped either way (1609 meters/1 mile) since the numerator and denominator are equivalent (1609 meters = 1 mile). You choose which way to flip it depending upon which unit you want to cancel out.

4. Sep 15, 2004

### Gokul43201

Staff Emeritus
Out of curiosity starsun, which grade is this for/are you in ?

5. Sep 15, 2004

### chem_tr

Dear starsun, you have not started the real thing yet... I hope you'll like chemistry lessons after you understand these unit conversions, You will need them in the future, so don't be confused.

Regards, chem_tr