science chp 1

• what is density?

  density is the mass per unit volume
• what is the correct order of the steps of the scientific method?


  observation ->hypothesis -> prediction -> testing the prediction
• what is the correct order of lighting a bunsen burner?

  close the air hole -> hold the lighter near the top of the bunsen burner -> turn on the gas tap -> ignite the bunsen burner with lighter -> open the air hole partially
• what is the s.i unit for length?

  metre (m)
• what is the s.i unit for mass?

  kilogram (kg)
• what is the s.i. unit for temperature?

  kelvin (K)
• what is the s.i. unit for time?

  second (s)
• what is an independent variable?

  it is a changed variable
• what is a dependent variable?

  the measured variable
• what is a control variable?

  the constant variable
• what is the use of a retort stand?

  to support apparatus during experiments
• what is the use of an evaporating dish?

  to evaporate the liquid from a solution to obtain the solute
• what is the use of the test tube?

  to contain or to heat small amounts of substances
• what is the use of a boiling tube?

  to contain or heat larger amounts of substances
• what is the use of a filter funnel?

  to separate a substance of different particle sizes with he help of a filter paper
• what is the use of a beaker?

  to contain for containing chemicals or heat up liquids. a beaker cannot be used to measure volume of liquids.
• what is the use of a flat bottom flask?

  to contain chemicals when preparing gases if the process requires no heating
• what is the use of the round bottom flask?

  to contain chemicals when preparing gases if the heating is required.
• what is the use of a conical flask?

  to collect chemicals or liquids
• what is the use of a wire mesh?

  to prevent direct heating of apparatus
• what is a qualitative data?


  it involves senses
• what is quantitative data?

  it involve senses and measurements using instruments
• what is accuracy?

  The closeness of a measurement to the true value.
• what is precision?

  Precision is a measure of how close multiple measurements are to each other.
• what are the 2 types of errors?

  zero error and parallax error
• what is zero error?

  zero error is when the electronic balance is not in use an displays a non zero number.
• what is parallax errors?


  errors due to viewing the marking on an instrument from the wrong angle.
• what is the meaning of the flammable sign?

  substance ignites or catches fire easily
• what is the meaning of the corrosive sign?

  substance may cause severe damage to body parts
• what is the meaning of the harmful or irritant sign?

  substance which causes irritation to the eyes, respiratory system and or skin
• what is the meaning of the acute toxicity sign?

  substance causes harmful effects to the body when breathed in, swallowed or upon contact with the skin
• what is the meaning of the radioactive sign?

  substance emits radiation that can kill living cellls
• what is the meaning of the oxidising substance?

  substance releases oxygen easily, which causes fire and or explosion
• what is the meaning of gases under pressure?

  gases stored in pressurised cylinders may explode when heated. may cause oxygen deficiency if gas is leaked in an enclosed space.
• what is the meaning of explosive?

  substances may cause fire or explosion or may cause explosion on contact with heat
• what is the meaning of biohazards sign?

  poisonous substances of a biological nature
• what is the environmental toxicity sign?

  substance has the potential to cause harmful effects on the environment
• what is the carcinogenicity/aspiration hazard?

  substance that can cause breathing difficulties, infertility, birth defects, damage to organs or cancer
• what is the use of the bunsen burner in the laboratory?

  it is used in the laboratory to heat things
• what are the advantages of luminous flame?

  it has a yellow flame, it is easy to see, its luminous and it is hot