# Study Guide

## part a

1. in a rectangular box the following measurements were found: six cibes fit exactly along one edge, and five cubes fit exactly along another edge. however after seven horizontal layers had been stacked in the box, a space at the top was left unfilled.

a. If the hight of the space was half the length of an edge of a unit cube, what was the volume of the box?

L x W x H ---- 6 x 5 x 7 x 5= 225 cubic centimeters

b. if the height of the space was 0.47 of the length of an edge of a unit cube, what was the volume of the box?

l x w x h= 6 x 5 x 7 x .47= 224.1 cubic centimeters

2. what is the mass of an iron bar that is 2cm x 4cm x 11cm (1cm of iron has a mass of 7.8)

2 x 4 x 11 x 7.8 ------ 88 x 7.8= 686.4 g

3. a volume of 87 cubic centimeters of dry sand is added to 46 cubic centimeters of water for a total volume of 104 cubic centimeters.

a. what is the volume of water tht fills the air spaces in the dry sand?

87-58= 29 cubic centimeters

b. what is the volume of the water that doesnt fill the air spaces in the sand

46-41= 5 cubic centimeters

4. to stay physically fit, Mr. Leeds is constatly training. He weighs a trim 178 lbs. What is his weight in kg?

2.2 divided by 178= 81 kg

5. use the following data to find the sensitivity of the balkance used

initial mass - 14.30

14.39-14.30=.09 .09/6 (number of yes)

sensitivity of the balance- .02

## part b

1. during the Heating baking soda lab a lab group does not realize that they have a hole in their rubber tubing. how will this affect their understanding fot the lab?

the bottle wont fill up with gas. therefore they will not come to the conclusion that the baking soda creates the gas.

## part c

1. here are the ingredients in Mr. Leeds famous pumpkin bread. next to each ingredient identify which are measured by mass, volume, or other means.

3 cups of flour- volume

1 tablespoon baking power- volume

11 pound can of pumpkin- mass

1/2 teaspoon vanillia- volume

cinnamon to taste- other

1/2 cup milk- volime

## part a

1. touching the tablet after the Mi and before the Mf will result in the mass decreasng. this will happen beucause the tablet is very chalky so you would be taking mass fromt he tablet when you touch it and it would affect your Mf.

2. A hole in the rubbertubing will result in a gain in mass. this will happen beucase all the gas that is being produced by the heat will escape throught the hole and result in a decrease in mass.

3. condensation on outside of bottle. if you dont wipe off the condensation the water on the outside of the bottle will add onto the orginal mass leading to a result in a gain of mass in the Mf.

## part b

1. furing the ice and water lab a lab group forgot to put the cap on their bottle. by the time they realized their mistake some condensation had already formed on the outside and inside of the bottle. they should start the lab over.

2. in all four experiments from chapter 2 the common theme involved investigating changes in mass of different states of matter. you now know that in all the labs there should be no change in mass beucase law of conservation of mass.

3. you are working in a class with no air conditioning and its 90 degrees F. your lab is to take the mass of water (that is 65 degrees f.) in a small plastic bottle with a cap on, then place the bottle in a walk-in freezer allowing the liquid to solidfy, then re-mass the bottle while in the freezer what is a possible error you should be aware of- condensation may form on the outside of the bottle during the Mi and then freeze.

4. a lab group dissolves 2 g of salt into 8 cubic centimeters of water in a beaker with no covoer. after a few days all of the water has evaporate. what will remain in their beaker?

2g of salt

## Test 3

when calculating the desnity of a rock (irregular shape) it would be an expimental error to find the volume prior to massing

in the density of a gas lab a student forgets to include the foil for the Mf, the result is the mass of the gas increases, and the density decreases.

epsom salt is the marketing name for which chemical compound? magnesium sulfade

## Lab Safety

For every lab

• must where goggles untill told you can take them off
• report all acciedents ammediately to Mr. Leeds
• use common sense

in case of emergency

• nurse- 2828

Safety equiptment in classroom

• fire extingisher
• fire blanket
• eye wash/shower

chemicals

• never tase chemicals
• alawsy waft liquids to detect odor
• never waft solids/powders
• avoid touching chemicals
• always wash hands with soap and water after a lab
• if chemicals touch skin: flush skin with water for 1 minute and notify mr. leeds

Glass

• hot glass looks the same as cold glass
• never use chipped or broken glass
• dispose of broken glass in the proper bin and tell mr. leeds
• never use force to remove or insert glass

Alcohol Burners

• roll up sleeves and put up hair
• never walk away from a lit burner
• never point the open end of a hot test tube at yourself or someone else
• do not look down into a test tube/beaker while it is being heated
• make sure burner is capped and flame is out when done

End of Experiment

• clean-up area and materials completely
• make certian that burner is out if one was used
• keep goggles on untill mr. leeds says to put them away

## Reaction in a Bag

• Purpose:

To record the observations that occurs when multiple chemicals substances are combined and to use my observations to understand the reactions of the chemicals.

chemical

A+B+liquid= gas

A+liquid= hot

B+liquid= cold

exothermic reaction- hot

endothermic- cold

## Heating Baking soda

expirimental error-

1. tube could be broken and would let water out of the bottle and into the container
2. the stirring rod could be dirty from a pervious class
3. stopper not snug and the gas escapes

terms-

control group- unheated test tube

expirimental group- heated test tube

indicator- tea (showed heated test tube was baking soda)

variable- somthing you want to measure

• independent varrible causes a change in the dependent varible
• heat/temp
• dependent variable- color of the tea
• control factor- we had control over it-
• same type of tea
• same amount of baking soda
• same amount of tea
• same stiring time
• same size test tube

## Volume

unit of measurement- cm3 (cubic centimeters)

volume- l x w x h

standard unit of length- meter (m)

1 centimeter (1cm)= .01

100cm= 1m

volume of liquids

• ise a graduated cylinder to measure volume
• ALWAYS check the intervals or scale
• units- millileters (ml) or cm3
• 1ml= 1cm3
• read rom bottom of the miniscus

## Box Questions 1-13 (no #2)

1. baking soda is used in baking becuase it relases gas when it is heated which helps dough/batter rise

3. 50 cubic centimeters of water are required to fill a graduated culinder to the 50 ml mark

4. the high or the width of box B is grader than the volume in box A

5. the volume of the stone that was added into the water which made it rise was 7 cm3.

6. a. 8 cubes are needed to build a cube that measures 2 cm along each edege

b. 27 cubes are needed to build a cube that measures 3 cm along each edege

c. 8cm3 is the voluime of the cubes in a. and 27 cm3 is the volume in b.

7. the box measuring 25 cm long, 16 cm wide and 15 cm deep has the larger volume

8. the divisions on the cone are not equally spaced because as the surface increases the depth decreases

9. a. b. c. look at book

10. look at the book

11. see book

13. when the graduated cylinder is narrow and tall the lines are farther apart than when the graduated cylinder in short and wide. this makes the reading easier.