Science Chapter 1 (S1) (must refer to notes when revising as well!!) Flashcards
variables, measuring instruments & apparatus, luminous and non luminous flames
What is an independent variable?
The variable that is changed (in a scientific experiment) to test the effects on the dependent variable
What is a dependent variable?
The variable being tested and measured (in a scientific experiment)
-is dependent on the independent variable
What is the function of a test tube?
to contain or heat small amounts of chemicals
What is a controlled variable?
Must be kept constant to stop them from interfering with the effect of the independent variable on the dependent variable.
what is the function of a boiling tube?
to contain or heat larger amounts of chemicals
what is the function of a measuring cylinder?
to measure a volume of liquid (to 0.5cm cube)
what is the function of a beaker?
to contain chemicals or heat liquids
what is the function of a conical flask?
to contain chemicals or to collect liquids
what is the function of a gas jar with lid?
for collecting gases
what is the function of the flat-bottomed flask?
to contain chemicals when preparing gases in a process which requires no heating
what is the function of a displacement can?
to aid in measuring volume of irregularly shaped solid objects
what is the function of a round-bottomed flask?
to contain chemicals when preparing gases in a process which requires heating
what is the function of a filter funnel?
to aid in the separation of an insoluble substance from a liquid
what is the function of an evaporating dish?
to evaporate the liquid in a solution over a Bunsen burner
what is the function of a tripod stand?
to support apparatus during heating?
what is the function of a Bunsen burner?
it is used for heating
what is the function of a wire gauze?
to support apparatus during heating
what is the function of a thermometer?
to measure temperature
what is the function of a retort stand?
to support apparatus during experiments
what is the function of a pipette?
to accurately measure out fixed volumes of liquids (eg: 20.0cm cube/25.0 cm cube)
what is the function of a graduated gas syringe?
to collect and measure volume of gases
what is the function of a burette?
to accurately measure out the volumes of liquids to the nearest 0.05cm cube
what is the function of a crucible (with cover)?
for heating a solid directly over a flame
how is a luminous flame produced?
it is produced when the air-hole is closed
explanation for how a luminous flame is produced?
insufficient oxygen causes incomplete combustion/burning of the gas and produces soot
how is a non-luminous flame produced?
it is produced when the air-hole is open
explanation of how a non-luminous flame is produced?
sufficient oxygen causes complete combustion/burning of the gas
what is a non-luminous flame used for?
for heating
what is a luminous flame used for?
when you need the flame to be easily visible/when leaving the flame for a while
colour of luminous flame
yellow
colour of non-luminous flame
pale blue
visibility of luminous flame
easily visible
visibility of non-luminous flame
not easily visible
steadiness of luminous flame
unsteady, flickering
strength of luminous flame
weak flame, less heat produced
steadiness of non-luminous flame
steady flame
strength of non-luminous flame
strong flame, more heat produced
soot production of luminous flame
produces soot and turns apparatus black
soot production of non-luminous flame
none
what is the hottest part of the luminous flame?
none
what is the hottest part of the non-luminous flame?
the hottest region of the flame is just above the tip of the dark blue zone
how does a strike-back occur?
the flame burns at the jet, the barrel becomes hot and poisonous gas is produced
what causes a strike-back?
a mixture of too much air and too little gas (fuel)
what to do in an event of an strike-back?
turn off gas tap immediately, let the Bunsen burner cool down before lighting it again.
