Midterm questions

• Which of the following is the function of a bunsen burner

  Provide heat
• What procedure should be followed when lighting a bunsen burner 


  close the air holes, gas regulator, open the gas outlet, light a matchstick, open the gas regulator slowly, then open the air holes to have the desired color of the flame
• When a lighted burner roars, it means that

  There is too much gas
• In measuring the mass of an object, what shouldn’t be done?

  If more than one rider is used, only get the weight of the rider with the smallest value
• Why does one NEVER weigh a hot object Hot objects create buoyancy effect by radiating energy in the form of heat and will appear to have a reduced mass.

  • Calculation done afterward will reflect low accuracy and poor precision leading to an appreciable error.
  • Precision and accuracy of the instrument will be affected
  • All of the above

  All of the above
• When heating a liquid in a test tube, always point the open part of the tube in which direction

  away from anybody
• How do you process smelling the odor of a chemical 


  Put the chemicals a few inches away from you then fan it towards your nose
• When inside a laboratory class, long hair must be?

  Must be tied properly
• Safety goggle are being used in the laboratory for what reason

  To protect eyes
• On your table you see an unlabeled beaker half-filled with clear liquid. The content...

  • is water therefore it is safe to touch.
  • could be water therefore go ahead touch it, there's no harm in testing.
  • could be acid therefore pour it in the table and see if it will react.
  • is unknown therefore leave it and inform your teacher.

  is unknown therefore leave it and inform your teacher.
• Papers, matchsticks and other insoluble solid materials should be discarded in?

  waste container
• Which of the following would you use to pick up the pieces of broken glasses

  Broom and dustpans
• Eating and drinking are NOT permitted inside the laboratory room because...

  • the lab would become messy and the chemicals might get contaminated.
  • there would not be enough time to finish the experiment since it takes time to eat.
  • the food might get contaminated and you could be poisoned.
  • there is no water for drinking.


  the food might get contaminated and you could be poisoned.
• Which of the following should be followed when asked to dilute an acid solution?

  • Add water into the acid slowly while stirring X
  • Add acid into water slowly while stirring
  • Add acid and water simultaneously then stir rapidly
  • Add acid and water simultaneously then stir slowly.

  Add acid into water slowly while stirring
• In heating liquids, why should the test tube be held at an angle of 45 degrees and likewise be moved back and forth?

  • To prevent the boiling of liquid.
  • To maintain the volume of liquid. Y
  • To prevent the evaporation of liquid.
  • To avoid spilling out of liquid from the test tube. 

  To avoid spilling out of liquid from the test tube
• In measuring the dimension of a rectangular object, you use

  ruler
• In reading the volume of a liquid, one should

  keep the eye on a level with the lower meniscus of the liquid
• Complete the statement: Precipitate is the substance 


  that has remained on the filter paper after filtration
• Which is heavier 1,00 kg of rice or 1000 g of flour?

  • 1.00 kg or rice is heavier than 1000 g of flour.
  • 1000 g of flour is heavier than 1.00 kg of rice.
  • They weigh the same.
  • Rice will always be heavier than

  They weigh the same
• Which of the following statements is FALSE?

  • A good buffer is one that contains a weak acid and its conjugate base.
  • A buffer solution is one that resists a change in pH when small amount of acid or base is added.
  • The capacity of the buffer is inversely proportional to the concentration of the buffer component.
  • The most effective buffer is one with equal concentration of basic and acidic components.
  • The most effective buffer is one with equal concentration of basic and acidic components.
• Consider a solution with 0.10 M CHCOOH and 0.20 M CH COONa. Which of the following statements is TRUE?A.If small amount of NaOH is added, the pH decreases very slightly.b. If NaOH is added, the OH ions will react with the CH COO ions.C. If a small amount of HCl is added, the pH decreases very slightly.d. If HCl is added, the H* ions react with CH COOH ions


  B. If NaOH is added, the OH ions will react with the CH COO ions.
• Dialysis process


  A selective passage of ions and small molecules through a semi-permeable membrane that will not allow proteins to pass through
• Dialysis process


  • A selective passage of ions and small molecules through a semi-permeable membrane that will allow proteins to pass through
• Dialysis process


  • A passage of ions and small molecules through a semi-permeable membrane that will allow proteins to pass through
• Dialysis process


  • A passage of ions and small molecules through a semi-permeable membrane that will allow solvents and proteins to pass through
• Surface tension is the tendency 


  of the liquid surface to contract
• Which of the following is/are effective in lowering surface tension

  • Soaps
  • detergents
  • sats of bile acids
  • all of these 


  all of these
• What is the positive result for molisch test

  Violet ring between the two liquids
• What is the positive test for Fehling’s?


  Red precipitate
• What does barfoed test for

  monosaccharides
• What is the positive result for barfoed‘s test 


  Red precipitate
• Mucic acid test is a test for the presence of

  galactose
• On hydrolysis, this sugar will also give positive result with Mucic acid test

  Lactose
• Which of the following is a test used to identify if the sugar is a pentose or hexose

  Bial’s Orcinol test
• In bial‘s orcinol will give a _________ if the sugar is pentose

  Blue/green color
• In bial’s orcinol will give a ________ if the sugar is hexose

  Muddy brown
• Which group of carbohydrates reacts most readily to he Seliwanoff test

  Ketoses
• Lactose will give a positive result for what tests?

  fehling’s test, benedict test, and molisch test
• What solvent is a fat soluble

  benzene
• When can you say that a particular compound gave a positive result with acrolein test

  Presence of pungent odor