Lab Safety-Measurement Lab

Study Guide

Lab Safety

For every lab:

  • goggles must be kept over your eyes at all times
  • report ALL accidents to Mr. Leeds
  • Common sense


Nurse extension:

2828


Safety Equipment:

  • fire extinguisher
  • fire blanket
  • eye wash/ shower


Chemicals:

  • never taste
  • waft liquids (never solids or powders)
  • avoid touching
  • wash hands with soap and water
  • if chemicals touch skin- flush skin with water for 1 min AND notify Mr. Leeds


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, put UP long hair
  • never walk away from lit burner
  • never point open end of hot test tube at yourself or someone else
  • do not look down into test tube/beaker while being heated
  • cap flame when done


End of Experiment:

  • clean-up area
  • make sure burner is out
  • keep goggles over eyes until Mr. Leeds says to put them away


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Reaction In a Bag

What was the red liquid?

Phenol Red


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ph scale

  • measures acidity
  • goes from 0-14
  • 0 is acidic
  • 7 is neutral
  • 14 is alkaline
  • below 7 turns yellow
  • above 8 turns pink


What was Solid A?

Calcium Chloride


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Was solid a acidic, neutral, or alkaline?

acidic


Hydrotropic

absorbes/ attracted to water


Calcium Chloride uses?

  • canned veggies (keeps from getting mushy)
  • electrolyte in sports drinks
  • flavor pickles (salty flavor)


What was Solid B?

sodium bicarbonate


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Was solid b acidic, neutral, or alkaline?

alkaline


Sodium bicarbonate uses?

  • baking
  • toothpaste
  • laundry detergent


Another name for sodium bicarbonate?

baking soda


What is a ph indicator?

Phenol Red


Produced Gas?

AB and water or red


Produced heat?

A mixing with red or water (exothermic reaction)


Experimental errors?

  • if there was a hole in the bag we would not see the gas being produced by the reaction


Scholar Reaction In The Bag Inquiry Demonstration and Lab Activity

Heating Baking Soda

What do you observe at the bottom of the test tube?

test tube was getting scorched on the outside


What do you observe near the top of the test tube?

condensation (moisture), bubbles forming, foggy, misty


What do you observe in the inverted bottle?

air is coming in and water is coming out


Where do you think the gas came from?

gas came from Baking Soda; gas left test tube


Where did the droplets on the test tube come from?

Baking Soda


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Describe the color of the liquid in each test tube.

Heated- murky, cloudy, darker

Unheated- clear, see through, light

ARe the two white powders the same substance?

no because the unheated is only baking soda and tea so the heated should be the same color, but they are different


In the heated test tube, did the baking soda dissolve into the tea?

yes


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In the unheated test tube, did the baking soda dissolve into the tea?

no


What was the control group?

unheated baking soda and tea


What was the experimental group?

heated baking soda and tea


Variable

a category you try to measure


Independent variable

causes a change in the dependent variable


example of independent variable

temperature, heat


example of dependent variable

tea color


control factors

  • using same tea for both test tubes
  • same amount of baking soda and tea
  • same size test tubes
  • same amount of stirring time


experimental errors

  • hole in tubing -> won't see gas fill bottle
  • stopper not snug -> won't see gas fill bottle
  • not cleaning stirring rod -> contamination


Is the amount of condensation that forms at the top of the heated test tubes more or less than the amount of baking soda being heated?

less because the condensation comes from the baking soda and it cannot produce more than itself


Why does baking soda rise?

when heated it releases a gas


Lab 1.1 Heating Baking Soda

Volume

cubic centimeters

cm3


cm3

cubic centimeters


What unit of measurement is used for volume?

cm3 (cubic centimeters)


How do you measure volume?

L x W x H


What is the standard unit of length?

meter


1 centimeter = ______________ meters

0.1


100 cm = ____________ m

1


What do you use to measure volume?

graduated cylinder


When measuring volume what do you always need to check?

intervals of scale


1 mL = ____________cm3

1


1 cm3 = _____________mL

1


How do you "zero" balance a scale?

  • push all riders to zero
  • use adjustment know if needed


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Single Pan Balance

When using a pan balance, what do you never switch?

pans


Pick up balance by _________________ only

red bar


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Why should you report the positions of the arrows to the nearest 0.01 cm and not to the nearest 0.1 cm?

it will be more accurate


What advantage is there to making graduated cylinders narrow and tall rather than short and wide?

lines are further apart because there's more depth due to lack of surface, therefore it will be easier to read

By Kaitlyn Ockerman

Period 2