U5 Part 1 Flashcards
synthesis (S) format
A+B → AB
decomposition (D) format
AB → A+B
single replacement (SR) format for a nonmetal
A+BC → BA+C
single replacement (SR) format for a metal
A+BC → AC + B
double replacement (DR) format
AB+CD → AD+CB
combustion (comb) format
CxHyOz+O2→CO2+H2O
when chemical bonds are made, energy is ____
released to achieve better stability
in order to break chemical bonds, energy is ___
absorbed
what is more stable - bonds or a molecule? why?
bonds are more stable because they create more stability. molecules consist of covalent bonds and making bonds releases energy so molecules can achieve better stability.By sharing their outer most (valence) electrons, atoms can fill up their outer electron shell and gain stability.
Enthalpy (H) describes____
the internal heat of a substance
Enthalpy change (AH) describes_______
the change of the internal energy before and after
Exothermic reactions _____ heat into the surroundings (heat ____). The heat sign is on the ____ side. The product is _____ stable with less ____
releases, exists, products, more, PE
Endothermic reactions ____ heat from the surroundings (heat ____ __). The heat sign is on the _____ side. The product is _____ stable with more _____
absorbs, goes in, reactants, less, PE
heat is turned into ______ ______ in chemical bonds
potential energy
tricks for balancing rxns
- group polyatomic ions
- write water as H(OH) when there is OH on the other side
- the coefficients in front of the hydrocarbons in combustion rxn can only be 1,2 or 4
- balance combustion rxn by the order C →H→O
