Al(NO3)3(aq) + 3NaOH(s) --> Al(OH)3 (s) + 3NaNO3 (aq)
The precipitate here is Al(OH)3 (s), since the solid reactant is the precipitate in the aqueous solution. Usually, it is okay to assume in basic chemistry that the transition metal is going to be part of the compound that is the precipitate, especially in an acidic salt and a strong base reaction that we have here.
In an experiement things that are changing are called variables.
20. Would be the right answer
The compound that was formed by the reaction of the first oxygen released by Cyanobacteria and iron are the metals of the earths crust. Cyanobacteria was the first organisms that used water instead of hydrogen sulfide or other compounds as a source of electrons and hydrogen for fixing carbon dioxide. Early Cyanobacteria inhabited marine sediments where Archean banded iron formations were deposited; consisting of reddish layers rich in iron oxide.
Answer:
See explanation below
Explanation:
The melting point (the temperature that it changes from solid to liquid) of a pure substance depends on its mass, the forces between its molecules, and the pressure of the system.
The melting point, or the freezing point, of a mixture, is a temperature between the melting point of its components. Salt has a huge negative melting point, so when it is added to the water, the melting point decreases from 0ºC to -21ºC approximately.
So, the water will only freeze again if the temperature becomes below -21ºC which is very difficult to happen.
