Chemical Changes Flashcards
(18 cards)
What is the reactivity of a metal related to?
It’s tendency to form positive ions
Explain how the reactivity of metals with water or dilute acids is related to the tendency of the metal to form it’s positive ion
What is an alkali
Soluble metal hydroxides
What is a base
Insoluble metal hydroxides and metal oxides
What does the salt produced in a reaction between acid and base/alkali depend on
— the acid used
(HCL produces chlorides, Nitric acid produces nitrates, SO4^2- produces Sulfates)
— the positive ions in the base, alkali, or carbonate
Describe the use of universal indicator (or wide range indicator) to measure the approximate pH of a solution
What are the electrodes usually made of in electrolysis?
Inherit carbon
—> unreactive so will not take place in reaction
Metals
• use and explain the terms dilute and concentrated (in terms of
amount of substance), and weak and strong (in terms of the degree of ionisation) in relation to acids
• describe neutrality and relative acidity in terms of the effect on hydrogen ion concentration and the numerical value of pH (whole numbers only).
Examples of strong acids
Hydrochloric, nitric, sulfuric
Examples of weak acids
Ethanoic, citric, carbonic
Concentration and pH
The stronger the acid, the lower the pH
—> as the pH decreases by one unit, the hydrogen ion concentration of the solution increases by a factor of 10
What causes the ions to move in electrolysis
Passing an electric current through electrolytes causes the ions to move to the electrodes.
lons are discharged at the
electrodes producing elements
Investigate pH changes when a strong acid neutralises a strong alkali
What is cryolite and why is it used in electrolysis
Why is anhydrous zinc chloride a safer alternative for practical work?
Negatives and positives of electrolysis
