Science Chapter 1 (S1) (must refer to notes when revising as well!!) Flashcards

variables, measuring instruments & apparatus, luminous and non luminous flames

1
Q

What is an independent variable?

A

The variable that is changed (in a scientific experiment) to test the effects on the dependent variable

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2
Q

What is a dependent variable?

A

The variable being tested and measured (in a scientific experiment)
-is dependent on the independent variable

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2
Q

What is the function of a test tube?

A

to contain or heat small amounts of chemicals

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2
Q

What is a controlled variable?

A

Must be kept constant to stop them from interfering with the effect of the independent variable on the dependent variable.

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3
Q

what is the function of a boiling tube?

A

to contain or heat larger amounts of chemicals

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4
Q

what is the function of a measuring cylinder?

A

to measure a volume of liquid (to 0.5cm cube)

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5
Q

what is the function of a beaker?

A

to contain chemicals or heat liquids

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6
Q

what is the function of a conical flask?

A

to contain chemicals or to collect liquids

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7
Q

what is the function of a gas jar with lid?

A

for collecting gases

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7
Q

what is the function of the flat-bottomed flask?

A

to contain chemicals when preparing gases in a process which requires no heating

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8
Q

what is the function of a displacement can?

A

to aid in measuring volume of irregularly shaped solid objects

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9
Q

what is the function of a round-bottomed flask?

A

to contain chemicals when preparing gases in a process which requires heating

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10
Q

what is the function of a filter funnel?

A

to aid in the separation of an insoluble substance from a liquid

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11
Q

what is the function of an evaporating dish?

A

to evaporate the liquid in a solution over a Bunsen burner

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12
Q

what is the function of a tripod stand?

A

to support apparatus during heating?

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12
Q

what is the function of a Bunsen burner?

A

it is used for heating

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13
Q

what is the function of a wire gauze?

A

to support apparatus during heating

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14
Q

what is the function of a thermometer?

A

to measure temperature

14
Q

what is the function of a retort stand?

A

to support apparatus during experiments

15
Q

what is the function of a pipette?

A

to accurately measure out fixed volumes of liquids (eg: 20.0cm cube/25.0 cm cube)

16
Q

what is the function of a graduated gas syringe?

A

to collect and measure volume of gases

16
Q

what is the function of a burette?

A

to accurately measure out the volumes of liquids to the nearest 0.05cm cube

17
Q

what is the function of a crucible (with cover)?

A

for heating a solid directly over a flame

17
Q

how is a luminous flame produced?

A

it is produced when the air-hole is closed

18
explanation for how a luminous flame is produced?
insufficient oxygen causes incomplete combustion/burning of the gas and produces soot
19
how is a non-luminous flame produced?
it is produced when the air-hole is open
20
explanation of how a non-luminous flame is produced?
sufficient oxygen causes complete combustion/burning of the gas
21
what is a non-luminous flame used for?
for heating
22
what is a luminous flame used for?
when you need the flame to be easily visible/when leaving the flame for a while
23
colour of luminous flame
yellow
23
colour of non-luminous flame
pale blue
24
visibility of luminous flame
easily visible
25
visibility of non-luminous flame
not easily visible
26
steadiness of luminous flame
unsteady, flickering
27
strength of luminous flame
weak flame, less heat produced
27
steadiness of non-luminous flame
steady flame
28
strength of non-luminous flame
strong flame, more heat produced
28
soot production of luminous flame
produces soot and turns apparatus black
29
soot production of non-luminous flame
none
29
what is the hottest part of the luminous flame?
none
30
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
31
how does a strike-back occur?
the flame burns at the jet, the barrel becomes hot and poisonous gas is produced
31
what causes a strike-back?
a mixture of too much air and too little gas (fuel)
32
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.