mistake deck Flashcards
a diagram shows an experiment to compare the rate of reaction when a metal is added to hcl
A) test tube A - zinc rocks and conc hcl
B) test tube B - copper balls and conc hcl
C) test tube C - zinc rocks and dil hcl
D) test tube D - copper balls and dil hcl
ans - A as even though the surface area of reacting zinc is less than the copper as it is in large rock form. zinc is much more reactive than copper looking at the reactive series.
which process is not used in the production of ethanol
A) addition of steam to ethene
B) fermentation
C) fractional distillation
D) reacting ethane with oxygen
ans - D
aq ammonium chloride + aq sodium hydroxide is heated below a red and a blue litmus paper what happens to the pieces of paper
A) blue and red change colour
B) blue changes colour and red doesnt
C) blue doesnt change colour and red changes
D) both dont change colour
ans - C as the ammonium gas will turn the red litmus blue
use of NaOH
making soap / degreasing / making paper / detergents / bio-diesel / paint stripper / clearing drains / alumina from bauxite / oven cleaner / bleach
A steel bicycle which had been left outdoors for several months was starting to rust.
What would not reduce the rate of corrosion?
A Remove the rust and paint the bicycle.
B Remove the rust and store the bicycle in a dry shed.
C Remove the rust and wipe the bicycle with a clean damp cloth.
D Remove the rust and wipe the bicycle with an oily cloth.
ans - C as the dampness of the cloth will hydrate the steel further
why do aluminium electricity cables have a steel core?
for strength
Why does aluminium react slowly (in general)
has an oxide layer that covers the surface
How does aluminium resist the acids in foods when it is used to make food containers
Prevents corrosion because of the oxide layer present on it
Why cant you extract aluminium using electrolysis of a an aq solution of it
Higher on reactivity series than hydrogen
therefore at cathode, hydrogen would form.
