chemistry Flashcards
what is the charge of a proton
positive
what makes up the nucleus of an atom
protons and neutrons
which particle determines what element an atom is
proton
which particles within an atom have a relative mass of 1
protons and neutrons
what is the charge of an electron
-1
what is an exothermic reaction
a reaction that releases thermal energy to it’s surroundings
what is an endothermic reaction
a reaction that takes in thermal energy from the surroundings
is breaking bond exothermic or endothermic
endothermic because it requires energy
what type of reaction produces a negative energy change
- -150kj/mol
- -330kj/mol
an exothermic reaction
what type of reaction produces a positive energy change
- 20kj/mol
- 44kj/mol
an endothermic reaction
how do we measure the acidity or alkalinity of a solution
using the pH scale
what do we call the pH of 7
neutral
what acid levels does the stomach acid normally have
around 2
how can pH solution be measured
- pH probe
- chemical indicator
why might using a pH probe be more reliable that using an indicator
- a probe produces more accurate results
- determining the colour of an indicator is subjective
what is the formula for nitric acid
NHO3
what is the formula for calcium carbonate
CaCO3
which substances are strong acids
- nitric acid
- sulfuric acid
- hydrochloric acid
which substances are weak acids
- carbonic acid
- citric acid
- ethanoic acid
what happens to the pH of hydrogen ions in a solution as the concentration increases
the pH will decrease
