Answer:
Humans started to use pesticides dating back to before 2000 BC.
Hope this helps ^-^
Explanation:
Answer:
4KNO3 ==> 2K2O + 2N2 + 5O2
Explanation:
It's a decomposition, but not a simple one.
KNO3 ==> K2O + N2 + O2 I don't usually do this, but I think the easiest way to proceed is to balancing the K and N together. That will require a 2 in front of KNO3
4KNO3 ==> 2K2O + 2N2 + 5O2
Now you have (3*4) = 12 oxygens. Two are on the K2O. So the other 10 must be on the O2
That should do it.
Answer:
3- is the charge and 8 dots on its Lewis dot structure.
Explanation:
Hello there!
In this case, since nitrogen is an element with five valence electrons (electrons on its outer shell), we infer that it needs three bonds to complete the octet, for which its charge, when forming nitride ions is 3-, which means it has received three electrons. Thus, when drawing the Lewis dot structure, it is evident that is will have 5+3 = 8 dots due to the electron reception.
Regards!
Answer:
c = 1.61 j/g.°C
Explanation:
Given data:
Mass of oil = 9 g
Heat added = 824 j
Initial temperature = 30°C
Final temperature = 87°C
Specific heat of oil = ?
Solution:
Specific heat capacity:
It is the amount of heat required to raise the temperature of one gram of substance by one degree.
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 = Final temperature - final temperature
ΔT = 87°C - 30°C
ΔT = 57 °C
Q = m.c. ΔT
824 j = 9 g × c × 57 °C
824 j = 513 g. °C × c
c = 1.61 j/g.°C
