Explanation:
An observation that can be counted is known as quantitative observation. On the other hand, an observation that does not contain any numerical data is known as non-quantitative observation.
Therefore, given observations are classified as follows.
(a) The Sun rises in the east - It is a non-quantitative observation as it cannot be measured.
(b) A person weighs one-sixth as much on the Moon as on Earth - It is a quantitative observation as it can be measured because we know the mass of moon. Hence, we can find out the weight of person.
(c) Ice floats on water - It is a non-quantitative observation as it cannot be measured.
(d) A hand pump cannot draw water from a well more than 34 ft deep _ It is a quantitative observation because it is measure that more than 34 ft deep water cannot be drawn by the pump.
Answer:
Fe + O2 + H₂O___ Fe2O3 + H₂O.
6Fe+302+H2O______2fe 203+H2O
<u>Answer:</u> The
for the reaction is -1406.8 kJ.
<u>Explanation:</u>
Hess’s law of constant heat summation states that the amount of heat absorbed or evolved in a given chemical equation remains the same whether the process occurs in one step or several steps.
According to this law, the chemical equation is treated as ordinary algebraic expressions and can be added or subtracted to yield the required equation. This means that the enthalpy change of the overall reaction is equal to the sum of the enthalpy changes of the intermediate reactions.
The chemical reaction for the formation reaction of
is:

The intermediate balanced chemical reaction are:
(1)
( × 6)
(2)
( × 3)
(3)
( × 2)
(4)

The expression for enthalpy of formation of
is,
![\Delta H^o_{formation}=[6\times \Delta H_1]+[3\times \Delta H_2]+[2\times \Delta H_3]+[1\times \Delta H_4]](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Bformation%7D%3D%5B6%5Ctimes%20%5CDelta%20H_1%5D%2B%5B3%5Ctimes%20%5CDelta%20H_2%5D%2B%5B2%5Ctimes%20%5CDelta%20H_3%5D%2B%5B1%5Ctimes%20%5CDelta%20H_4%5D)
Putting values in above equation, we get:
![\Delta H^o_{formation}=[(-74.8\times 6)+(-185\times 3)+(323\times 2)+(-1049\times 1)]=-1406.8kJ](https://tex.z-dn.net/?f=%5CDelta%20H%5Eo_%7Bformation%7D%3D%5B%28-74.8%5Ctimes%206%29%2B%28-185%5Ctimes%203%29%2B%28323%5Ctimes%202%29%2B%28-1049%5Ctimes%201%29%5D%3D-1406.8kJ)
Hence, the
for the reaction is -1406.8 kJ.
<span>(3) amina ........................</span>