Answer:
1. Oxygen
Total no of electrons 8
Group 6
No of valence electrons 6
Period 2
No of valence shell 2
2.Sodium
Total no of electrons 11
Group 1
No of valence electrons 1
Period 3
No of valence shell 3
3. Phosphorus
Total no of electrons 15
Group 5
No of valence electrons 5
Period 3
No of valence shell 3
Answer:
See the answer below
Explanation:
<em>First, it should be understood that an endothermic reaction is one that absorbs energy in the form of heat from the surrounding.</em> The products of endothermic reactions usually have higher energy than their reactants. Hence, the ΔH° which is referred to as the enthalpy change is usually positive.
<u>Forgetting to cover the coffee-cup calorimeter means some of the heat energy absorbed by the reactants would be exchanged back to the surroundings - a loss.</u> It also means that the enthalpy change would be smaller compared to if the cup had been covered because some of the heat has been lost to the surrounding.
Atoms are electrically neutral because they have equal numbers of protons (positively charged) and electrons (negatively charged).
Answer:
Xà phòng hoá hoàn toàn 40,8 gam phenyl axetat trong dung dịch NaOH dư. Cô cạn dung dịch sau phản ứng thu được khối lượng muối làA. 59,4 g. B. 24,6 g. C. 39,6 g.D. 64,8 g.