7. How much 0.5 M KCl solution is required to react completely with 100 mL of 2M AgNO3 solution? KCl + AgNO3 → AgCl + KNO3

8. In the previous question, the AgCl produced is nonsoluble and forms a precipitate. If this precipitate is weighed and dried, what mass of AgCl would you expect to find?

9. A fixed volume of 15 cm3 of N2 at STP is reacted with excess H2. What volume of NH3 is produced at STP?

N2 + 3H2 → 2NH3

10. 50 mL of 2.0M NaBr is reacted with excess Cl2. The Br2 gas produced is collected. What volume would the gas occupy at 298 K and 1 atm?

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6

answer is: nuclear fusion produces elements that are heavier than helium.

nuclei combine to form a heavier nucleus, releasing energy.  

for example, fusion of hydrogen atoms at the sun.  

this fusion nuclear reaction is in the inner core of the sun and hydrogen (atomic number 1) is conveted into helium (atomic number 2).  

the inner core is the central region of the sun and all solar energy is produced in the core by nuclear fusion.