Acids, Alkalis, And Salts Flashcards
How did people identify acids ?
From their taste and from their sour taste
How did people identify alkalis ?
From their taste and from their soapy feel
What are indicators ?
Special dyes that change color in acids and alkalis
What is litmus ?
Indicator that is red in acid and blue in alkali
What is universal indicator ?
Tells us how strongly acidic or alkaline a substance is
When does methyl orange turn red ?
When in an acidic solution
When does methyl orange turn yellow ?
When it’s either neutral or alkaline
What are the colors of phenolphthalein ?
Colorless as neutral and acid, but pink when alkaline
What happens if the acid is stronger ?
The more dangerous and corrosive it is a
What are the main points in the Ph scale ?
Ph 1 is a strong acid
Ph 6 is a weak acid
Ph 7 is neutral
Ph 8 is a weak alkali
Ph 14 is a sting alkali
What is neutralisation ?
A réaction where an acid reacts with an alkali to for a neutral solution
State examples of a neutralisation reaction ?
Antacids, farmers neutralize soils
Universal indicator and the ph scale :
How does hydrochloric acid not burn through the stomach ?
The stomach has a protective layer
Acids :
Acids form acidic solutions in water
Acids are sources of hydrogen ions, H+
Ex: hydrochloric acid produces hydrogen ions
HCI(aq)—> H+(aq) + Cl-(aq)
What are acids ?
Substances that :
Turn litmus red
Have a ph below 7 and turn universal indicator yellow, orange or red
They contain hydrogen ions ( H+ )
Ex: hydrochloric acid is a strong acid but Ethanoic acid (vinegar) is a weak acid
Alkalis :
They form alkaline solutions in water
Alkalis are sources of hydroxide ions ( OH- )
Ex: sodium hydroxide produces hydroxide ions:
NaOH(aq) —> Na+(aq) + OH-( aq )
What are alkalis ?
Substances that :
Turn litmus blue
Have a ph above 7 and turn universal indicator blue or purple
Contain OH- ions
Ex:
sodium hydroxide is a strong alkali
Ammonia is a weak alkali
What happens with atoms with incomplete outer electron shells ?
They are unstable
How can atoms obtain a full outer electron shell and be stable ?
By gaining or losing electrons
How do atoms become ions ?
Atoms with incomplete outer electron shells are unstable. By either gaining or losing electrons, atoms can obtain full outer electron shells and become stable.
When this happens, atoms have an unequal number of protons and electrons and so have an overall charge.
What is neutralization?
When an acid and an alkali react in a neutralisation reaction the hydrogen ions react with the hydroxide ion to produce a neutral substance.
What is the equation for neutralisation ?
Acid + Alkali→Water
What happens when an acid and an alkali react in a neutralisation reaction ?
the hydrogen ions react with the hydroxide ion to produce a neutral substance.
Hydrogen ion (acid) = H+ Hydroxide ion (alkali) = OH-
H+ +OH-➔H2O
What do all acids contain ?
H+ ions
What do all alkalis contain?
OH- ions
Explain the concentration of ions ?
The pH of a solution is a measure of its concentration of hydrogen ions:
• the higher the concentration of H+ ions in an acidic solution, the lower the pH
• the lower the concentration of H+ ions in an acidic solution, the higher the pH
