c01 experimental chemistry Flashcards
(23 cards)
apparatus to measure time and how accurate its readings are?
digital stopwatch to 0.01s or analogue stopwatch to 0.1s
apparatus to measure temperature and how accurate its readings are?
digital thermometer to half a division /analogue thermometer to 0.5 degree celsius (alcohol and mercury)/temperature sensors or probes that are connected to data loggers
apparatus to measure length and how accurate its readings are?
metre rule to 0.1cm/measuring tapes to 0.1cm or 0.5cm
apparatus to measure mass and how accurate its readings are?
electronic balance to 0.01g
apparatus to measure volume and how accurate its readings are?
pipette measures 10cm^3 or 25cm^3/volumetric flasks measures larger accurate fixed volumes/measuring cylinder measures to 0.5cm^3/burette measures to 0.05cm^3
what is the SI unit for time, temperature, length, mass and volume?
second(s),kelvin(K),metre(m),kilogram(kg),cubic metre(cm^3)
how do you convert temperature in degree celsius to kelvin?
temperature in degree celsius +273 = temperature in K
what gases are less dense than air?
ammonia (NH3) and hydrogen (H)
what gases are denser than air?
chlorine(Cl2), hydrogen chloride(HCl), nitrogen dioxide(NO2), sulfur dioxide(SO2), carbon dioxide(CO2), oxygen(O2)
what gases are soluble in water?
ammonia (NH3), chlorine(Cl2), hydrogen chloride(HCl), nitrogen dioxide(NO2), sulfur dioxide(SO2)
what gases are slightly soluble in water?
carbon dioxide(CO2), oxygen(O2)
what gases are insoluble in water?
hydrogen(H)
what can gases can be dried using concentrated sulfric acid?:
most gases including chlorine(Cl2),hydrogen(H),hydrogen chloride(HCl)
what gases can be dried using calcium oxide?
ammonia (NH3)
what gases can be dried using fused calcium chloride?
hydrogen(H), nitrogen (N), carbon dioxide (CO2)
steps to answering crystallisation questions?
(H)eat to saturation
(C)ool to form crystals
(F)ilter to collect crystals as residue
(W)ash with a little cold distilled water (to reduce the amt of cystals that dissolve)
(D)ry between pieces of filter paper
what are the boiling chips used for?
for smooth boiling, to prevent splashing of water
why does water enter from the bottom of the condenser and exit out from the top?
because we need to fully fill the condenser to constantly circulate cold water to allow condensation to occur in the condenser.
what are some things to note when doing paper chromatography?
- draw start line with pencil
why?: pen may be soluble in solvent and produce additional spots - draw start line above solvent level
- lid to reduce evaporation of solvent
- draw solvent front with pencil
how to calculate retention factor value and round to what dp?
distance travelled by substance/distance travelled by solvent round to 1d.p or 2d.p
what can you use to if there is a colourless spot on a paper chromatogram?
spray locating agent or use uv light, or use both
what is the purpose of the glass beads in the fractionating column?
glass beads allows for better separation as it provides a large surface area to volume ratio for cooling of the vapors
how is the boiling point or melting point affected by an impure substance
the substance melts or boil over a range of temperature. (boiling point raises, melting point lowers)
