Help with beginner chem stuff

In summary, the speaker has a chemistry teacher who does not teach from the book and expects them to read and understand it completely. They have questions about non-chemistry topics and unit conversions, and the teacher advises them to use dimensional analysis and a conversion chart. The speaker is inquiring about the grade level and the teacher encourages them to continue learning unit conversions for future use.
  • #1
starsun
6
0
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 can't 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!
 
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  • #2
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
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
Out of curiosity starsun, which grade is this for/are you in ?
 
  • #5
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
 

1. What are some common lab safety rules that beginners should know?

Some common lab safety rules include wearing appropriate personal protective equipment (PPE) such as goggles and lab coats, properly disposing of chemicals and waste, keeping work areas clean and organized, and following specific instructions for handling hazardous materials. It is important to always read and understand the safety protocols before beginning any experiment.

2. How do I properly measure and mix chemicals?

To properly measure and mix chemicals, you should use graduated cylinders, beakers, or other lab equipment that is specifically designed for this purpose. Make sure to use the correct units of measurement and follow the instructions provided in your experiment. Always add acids to water slowly and carefully, and never mix chemicals that are not instructed to be mixed together.

3. What is the difference between a physical and chemical change?

A physical change involves a change in the physical properties of a substance without altering its chemical composition. This could include changes in state (solid, liquid, gas), shape, or size. A chemical change, on the other hand, involves a change in the chemical composition of a substance and results in the formation of new substances with different properties.

4. How do I balance chemical equations?

To balance a chemical equation, you must make sure that the number of atoms of each element on the reactant side is equal to the number of atoms of each element on the product side. This can be done by adding coefficients (numbers in front of each compound) to balance the equation. Remember to never change subscripts, as this would change the chemical formula.

5. What are some common lab equipment and their uses?

Some common lab equipment includes beakers (used for holding and mixing liquids), test tubes (used for small-scale reactions), graduated cylinders (used for precise measurements), Bunsen burners (used for heating substances), and pipettes (used for transferring small amounts of liquid). Other equipment may include balances, funnels, and thermometers, among others. It is important to familiarize yourself with the uses of each equipment before using them in an experiment.

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