Answer:
10
Explanation:
Sodium has 11 electrons when it is neutral. This sodium isn't neutral, it has a +1 charge. The +1 charge means it has lost 1 electron.
11 - 1 = 10
Answer: 
Explanation:
According to ideal gas equation:

P = pressure of gas = 0.987 atm
V = Volume of gas = 12 L
n = number of moles = 0.50
R = gas constant =
T =temperature = ?


Thus the temperature of a 0.50 mol sample of a gas at 0.987 atm and a volume of 12 L is 
Answer:
When iron sulfide is exposed to oxygen it reacts rapidly, releasing large amounts of heat.
Explanation:
i took this from my notes- so whatever aligns with that. sorry if this didnt help but i think its genuinely c heating
Answer:
Mass of water = 41.8 g
Explanation:
Given data:
Mass of water = ?
Change in temperature = 3.0 °C
Specific heat capacity = 4.184 j/g.°C
Heat absorbed = 525 j
Solution:
Formula:
Q = m.c. ΔT
Q = amount of heat absorbed or released
m = mass of given substance
c = specific heat capacity of substance
ΔT = change in temperature
ΔT = 3.0°C
Now we will put the values in formula.
525 J = m × 4.184 j/g.°C × 3.0°C
525 J = m × 12.552 j/g
m = 525 J/ 12.552 j/g
m = 41.8 g
An isotope is when a normal atom has too many neutrons and its weight has been offset.