Science Quiz #2 Study Guide

By: Brooke Luckman Per. 2

Safety Handout

  • Nurse extension is 2828
  • Hot glass and cold glass look the same
  • Always waft liquid chemicals (NEVER solids/powders)
  • Do not look down into a test tube while being heated
  • Never use force to remove or insert glass



Reaction in a Bag

  • Phenol red is used as a ph indicator (Below 7 on ph scale turns yellow and about 8 turns pink)
  • Calcium Chloride (calcium and chloride) used to keep things fresh, electrolytes, and salty flavor
  • Sodium bicarbonate (baking soda) not acidic, used in baking, toothpaste, laundry detergent
  • When A is mixed with red or water it creates an exothermic reaction (a chemical reaction accompanied by the evolution of heat)

Heating Baking Soda

  • In the inverted bottle the water decreases
  • The gas comes from the baking soda heated with the air in the test tube
  • The droplets in the test tube also came from the baking soda
  • The heated tea test tube is not the same as the non heated test tube because the color is different which means they are two different substances.
  • The control group: unheated baking soda/tea
  • Experimental group: heated baking soda/tea
  • Independent variable: something that will cause a change in the dependent (the temperature)
  • Dependent variable: the tea color
  • Control factors: things that we can control (Using the same amount of tea/baking soda; same type of tea; same size test tube; same amount of stirring time)
  • There is less or the same condensation as baking soda because the condensation comes from the baking soda, so it cannot produce more than itself
Lab 1.1 Heating Baking Soda

Volume

  • Unit of measure: cm3 (cubic centimeters)
  • Volume Formula: LxWxH
  • Standard unit of length: meter (m)
  • 1cm = .01 m 100cm=1m
  • Unit cube: a small cube 1cm on each edge one cubic centimeter=1 cm3
  • Always use a grad. cylinder to measure
  • Unit: milliliters (mL) or cm3
  • 1mL = 1cm3



Single Pan Balance

  • Check that pan is clean and dry
  • Always "zero" balance before each massing
  • Push all riders to zero (left) and use adjustment knob if needed
  • NEVER switch pans
  • Pick up balance by red bar only
  • DON'T zero balance when done


Measuring

  • Always estimate to one decimal place more than your given
  • The advantages of a graduated cylinder being narrow and tall is that the lines are further apart because there's more depth due to lack of surface (easier to read)
  • On a cone shaped graduated the divisions are not equally spaced because as the surface increases the depth decreases.