Acids have a pH of _____ than __.
less than 7
What is an OH- ion called?
a hydroxide ion
A substance contains an excess of H+ ions. What is its pH?
It is acidic, so it is lower than 7.
What does "pH" actually stand for, anyway?!?!
The German "potenz H(ydrogen)", which means the power of the hydrogen-ion concentration.
Universal Indicator is green in the presence of a substance. What does this indicate?
The substance is neutral.
Non-metals generally form _______ oxides that dissolve in water to form _______ solutions.
acidic
A substance contains an excess of OH- ions. What is its pH?
It is alkaline, so it is higher than 7.
What adjective is the opposite of "dilute"?
concentrated
What adjective means "can eat through material"
corrosive
A substance turns the Universal Indicator bright red. What does this "indicate"?
It is very acidic.
Alkalis have a pH _________ than __.
greater than 7
How can we use litmus paper to test the pH of gases?
The litmus paper must be damp.
Name a pH indicator other than litmus or Universal Indicator.
methyl orange or phenolphthalein (also hydrangea flowers, turmeric, and anthocyanins)
Which acid is present in orange juice?
citric acid
Give an exception to the rule that "Oxides of non-metals are acidic oxides."
Water. It can be considered hydrogen oxide and a neutral oxide.
The acidic oxides of sulfur, phosphorus, and carbon produce acids when dissolved in water. When pure, they are ________ molecules.
covalent
The more acidic the solution, the ______ the pH.
lower
What acid is present in vinegar?
acetic acid (ethanoic acid)
Metals form oxides that are solids. If they dissolve in water, these oxides give _______ solutions.
alkaline
What kind of acid is in the atmosphere of Venus?
sulphuric acid (due to volcanic activity)
Alkalis turn litmus paper ______.
blue
Acids turn litmus paper _____.
red
What adjective is the opposite of "concentrated"?
dilute
What is the most accurate method to measure pH?
Use a pH meter which uses an electrode to measure pH electrically.