Answer:
The answer is melting and freezing point.
Explanation:
Answer: O potássio possui apenas um elétron de valência. ... Considerando que o cálcio possui dois elétrons de valência, requer mais energia para a remoção de um elétron de valência. Devido a esse potássio, é mais reativo que o cálcio.
Explanation:
Explain whether this is a chemical or physical change, and why. does it involve elements, compounds, mixtures, or pure substances?
If the process involves a chemical reaction then surely it is a chemical change where new bonds are being formed from the collision of the reactants.
Describe how many atoms are involved before and after. what do you notice about the number of atoms?
From the balanced chemical reaction, we see that we need 1 mol of N2 gas and 3 mol of H2 in order to form 2 mol of NH3.
Answer:
open system
Coffee held in a cup is an open system because it can exchange matter water vapors and energy heat with the surroundings.
