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Is bond breaking endothermic or exothermic?
Bond breaking is endothermic
Is bond forming endothermic or exothermic
Bond forming is exothermic
What is the formula for Enthalpy change (◇H)
◇H=Total energy absorbed to break bonds-Total energy released in making bonds
What is the formula for making esters
Alcohol + carboxylic acid --> ester + water
What colour is phenolphthalein in alkali and acid?
Phenolphthalein is pink in alkali and colourless in acid.
Acid + metal -->
Acid + metal --> salt + hydrogen
Describe what would happen if you were to add magnesium to cold dilute acid?
Magnesium would react vigorously and produce loads of bubbles.
Describe how zinc and iron react with dilute acids?
Both zinc and iron react slowly with dilute acids but more strongly if you heat them up.
Describe the test for how reactive metals are.
Set up three boiling tubes with equal volumes of HCL and SO4. Place the metals in each one, making sure they are the same size.
The more reactive the metal the higher the rate at which the bubbles of hydrogen are produced.
Test for hyrogen by a burning split, the more reactive the metal the louder the 'squeaky pop'.
What are the percentages of air?
Nitrogen:78%
Oxygen:21%
Agron:0.9%
Carbon dioxide:0.04%
Metal + water --> ?
Metal + water --> metal hydroxide + hydrogen
Metal + steam -->?
Metal + steam --> Metal oxide + hydrogen
Explain how the amount of energy given off is because of reactivity.
The more reactive the metal the more energy given off.
What metals react with only steam not water?
Less reactive metals like magnesium, zinc and iron only react with steam.
Aqueous ammonia gives off ammonia gas. Hydrochloric acid (HCI) gives off hydrogen chloride gas.
...you'll get a white ring of ammonium chloride
forming in the glass tube.
The NH3 gas diffuses from one end of the tube and the HCI gas diffuses from the other. When
they meet they react to form ammonium chloride.
The ring doesn't form exactly in the middle of the
glass tube -it forms nearest the end of the tube
where the hudrochloric acid was.
Explain these results of the ring formed.
The particles of ammonia are smaller and lighter than the particles of hydrogen chloride, so they diffuse through the air quicker.
Rf=
Rf= Distance travelled by solute
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Distance travelled by solvent