If two objects have different temperatures which direction will heat move for how long

Which of the following is always a reactant in a combustion reaction? oxygen nitrogen hydrogen carbon

2pos suppose an object in free fall is dropped from a building. its starting velocity is 0 m/s. ignoring the effects of air resistance, what is the speed (in m/s) of the object after falling 3 seconds? give your answer as a positive decimal without units. answer here

In which situation can a mixture always be called a solution