Science Exam

Introduction to Physical Science

Science exam

Cover: Lab Safety – 3.8

Multiple choice, true/false, matching

- Lab questions (exp. Errors, etc.)

- Matching terms


Reaction in a Bag

Purpose of the Lab: To record and observe what happens when you mix chemical substances together.

Red Liquid = Phenol Red

-used as an indicator for Ph scale

-Below 7 = yellow

-Above 8 = pink

Solid A = Calcium Chloride

-Acidic (Mildly)

-hydrotropic = attracted to water

*Uses= Canned seafood (Keeps preserved), electrolytes in sports drinks, and flavors pickles.

Solid B = Sodium Bicarbonate (Baking Soda)

-Not Acidic

*Uses = Baking, toothpaste, laundry detergent, and cat litter

Exothermic Reaction = Gives off heat

Endothermic = Gives off coldness

Experimental Errors = Hole in the bag

Safety!

For Every Lab:


Goggles must be kept OVER YOUR eyes

Report ALL accidents to Mr. Leeds

Use common sense


In Case of Emergency

Nurse: Ext: 2828


Safety Equipment:

Fire Extinguisher

Fire Blanket

Eye wash/shower


Chemicals

Never taste chemicals

Always waft liquids

Never waft solids or powders

Avoid touching chemicals

Always wash hands with soap and water


Glass

Hot Glass looks like Cold Glass

Never use chipped or broken glass

Never use force to remove or insert glass


Alcohol Burners:

Roll up sleeves, puts up long hair, not pull back

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 sure that burner is out if one was used

Keep goggles on until Mr. Leeds says to put them away

Heating Baking Soda Terms

Control Group = Unheated


Experimental Group = Heated

Indicator = Tea (Shows heated test tube is not baking soda)

Variable = Something you try to measure

Independent Variable = causes a change in dependent variable (Temperature)

Dependent Variable = Color of Tea

Control factors = same type of tea

Experimental Errors =

Hole in tubing -> Wont see bottle filled with gas

Stopper not Tight

Stirring rod not clean

Big image

Test Number 1

In a rectangular box the following measurements were found: Six cubes 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 two was left unfilled.


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

225


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?

2.241 cm3


What is the mass of an iron bar that is 2cm x 4cm x 11cm? (1cm3 of iron has mass of 7.8g)

686.4 cm



To stay physically fit, Mr. Leeds is constantly training (and injuring himself). He weighs a trim 178 lbs. What is his weight in kilograms?



178/2.2 = 81

Measurement

Saucepan: Mass

~Histogram Rule~

If data falls on a line, it is graphed in column to the right.


Conclusions

Reaction in a bag:



The purpose of the Reaction in a Bag lap was to record the observatio­ns that occur when multiple chemicals substances are combined and to use my observations to understand their reactions of the chemicals. We were given two white substances and combined them with a red liquid, then sealed it in a plastic bag to watch it react. We saw it turn yellow; it felt hot and a little bit cold in the corner, and filled with gas. I have come to the conclusion that when the solids and the liquids were combined they reacted and there was a color change, it changed temperature, and there was a gas. I have come to this conclusion because during this lab the data and my observations have shown that when substance A mixes with a liquid it forms an exothermic reaction and when substance A and B combine it creates and endothermic reaction. When substance A and B combine, it creates a gas.


Heating Baking Soda



The purpose of the lab was to see what happens when you heat baking soda. We got one test tube and connected it with a bottle that had water in it. The water was the same level as the water in the bin that it sit in, so gravity did not affect the water in the bottle. A tubing connected the bottle and the top of the test tube. We then heated the test tube and found that when it was heating, condensation was happening at the top of the test tube, and the water level was dropping in the bottle. We then mixed tea with the heated test tube and another test tube with baking soda. We compared that the one that was heated was more foggy then the one that was not heated. I have come to the conclusion that heating baking soda changes the chemicals which gives off a different reaction.


Measuring Volume by displacement



The purpose of this lab is to use the displacement of water method to determine the volume of dry sand that is air space. We first measured 31 cm3 of dry sand and put it into one test tube. We then measured 17 cm3 of water and put it into another test tube. We poured the water into the sand and found that it was 36 cm3. To determine the volume of sand that is air space, we subtracted the volume of sand alone to the 36 cm3 and got 12 cm3. I have come to the conclusion that the percent of sand that is air is 39% because when you divide what is air and dry sand, it becomes 39.

The Sensitivity of a Balance



Part A

The purpose of part A is to determine if you mass the same object repeatedly the mass remain. Also, to see how different the masses of two objects must be for our balance to detect the difference. First, we put a penny on a scale and weighed it, then wrote it done. Next, my partner would do the same but not tell me her answer. I would then weigh it again and not tell my partner the answer, and she will do the same. After all four times of weighing it, we share answers. We do the same thing with the stopper. I have come to the conclusion that because we weighed each thing multiple times, we got difference answers. Because we did this, I could tell that the numbers that are more alike are more accurate.

Part B

The purpose of part B was also to determine if you mass the same object repeatedly the mass remain. Also, to see how different the masses of two objects must be for our balance to detect the difference. First, we cut out a 20 x 20 square of paper and measured it. We then measured a single square and a group of four. After this, we would put a group of 4 on the stopper then measure it. We would repeat this nine more times after this. I have come to the conclusion, that after getting different numbers in no specific order, there is not pattern.

Mass of Dissolved Salt



The purpose of the lab was to determine if the mass of salt decreased when salt dissolves in water. We first checked if the dry was cap and massed it, we massed it to determine how much to take off. We then added 2g of salt to the cap and filled a bottle 2/3 full with water. We then massed the salt and water together and then massed the salt in the water and shaken. We then found the change between the two by subtracting them. I have come to the conclusion, that the salt mixed with the water weighs less than the one without it mixed. I have come to this conclusion because the mass final mass weighs less, since the salt dissolved in the water.

Ice Ice Baby


The purpose of this lab was to determine if the mass of ice will increase, decrease, or stay the same when it melts. First, we had to zero the balance and make sure the cap was dry. Next, we massed the bottle and cap. We then put a piece of ice in the bottle and massed it. After, we let the ice melt and then massed the bottle with the ice. I have come to the conclusion that when the ice melts, it becomes heavier. I say this because the ice does not take up as much space, but when it melted it covered the bottom of the bottle, making it heavier.



Mass of Copper and Sulfur



The purpose of this lab was to determine if the total mass increases, decreases, or stays the same when copper and sulfur are heated together. First we checked the pan to make sure it was zero balanced. Then we added a test tube, band, and rubber sheet onto a massed it. Then we added 2g of copper and massed it. We then put the copper into the test tube. Next, we massed a paper towel, and then added 1g of sulfur to it. We then added the sulfur to the copper in the test tube and closed the lid with the rubber sheet and band. We massed the test tube unheated and had Mr. Leeds check our station. After, we lit the burner and heated the mixture until it gives off a reaction. We then capped the burner and let it cool. Lastly, we measured the mixture heated and cleaned up. When the mixture heated it turned into dark goo and started to rise with a lot of gas coming out of it. I have come to the conclusion that once you heat the test tube, it adds more mass. I have come to this conclusion because the heated mixture weighed more than the non-heated. I think this happened because the two chemicals blended together, and it created a gas that added more mass.

The Mass of Gas



The purpose of this lab was to determine if the mass will increase, decrease, or stay the same when a solid and liquid produces a gas. First we cleaned and zero balanced the scale. Next, we filled the glass bottle 1/3 full with water. After we dried the cap, we place a piece of Alka-Seltzer into it and massed the bottle, cap, and tablet. Next, we put the tablet into the bottle and waited 30 seconds for it to dry. After, we slowly loosened the cap and massed it again. We repeated this process two more times. After doing this lab, I have come to the conclusion that when the solid and liquid produced a gas, it took away mass. I have come to this conclusion because according to my data, two out of the three times I did this experiment, it had less mass when the solid dissolved into the liquid.

Density of a Solid



The purpose of the lab was to utilize density to decipher if 3 metal objects are made of the same substance. First, I checked to make sure the pan was clean and that it was zero balanced. Next, I massed the two cubes. After, I answered blue dot question number 1. Then, I measured the slab. After I measured the slab, I answered blue dot question 2. Next, I found the dimension of the three objected by measuring them with a ruler. After, I found the volume and density. I then massed a rock and found the volume for it. I have come to the conclusion that all three objects are not made of the same substance. I have come to this conclusion, because according to my and the class’s data, the volume, mass, and density of the three objects were different.

Density of a Liquid



The purpose of this lab was to use density to compare two liquids to observe if they are the same substance. First, we cleaned the pan and zero balanced it. Next, we wafted the liquids to see if we knew what they were. Next, we massed the empty cylinder. After, we put in 10 cm3 of liquid A and massed it. We then calculated the mass by subtracted the empty cylinder data with the cylinder and liquid data. Lastly, I found the density of the liquid by dividing the mass and volume. I have come to the conclusion that liquid A is denser then liquid B. I have come to this conclusion, because according to the class data, most of the Liquid As was denser than liquid B.

Density of a Gas



The purpose of this lab was to produce and collect a gas in order to accurately discover the density of a gas. First, I cleaned and zero balanced the balance. Next, I massed the two half tablets of Alka-Seltzer, and a test tube with 5 cm3 of water. Next, I found the volume. Next, I arranged the apparatus. After Mr. Leeds has checked it, I dropped two half tablets in the water and quickly inserted the stopper in the test tube. Then, I waited 10 minutes for the reaction. After, I removed the delivery tube from the bottle and removed the stopper. I then massed the bottle and found the volume of the new water. After, I cleaned up and calculated the density. I have come to the conclusion, that the density of gas is between 1.5 to 3.5. I have come to this conclusion because according to the class data, this was the density.