Answer:

Explanation:
First, we find in the tables the ΔH of formation of each compound. As you can see in the (image 1)
Then we solve the ecuation for ΔH°reaction
ΔH°reaction=∑ΔH°f(products)−∑ΔH°f(Reactants)
ΔH°reaction= (-2* 393.5 - 2*285.8) - (52.4 + 0) kJ/mol
ΔH°reaction = -1.41 *10^3 kJ/mol
Answer:
Both require time, but velocity requires displacement and speed requires distance
Explanation:
For calculating speed we require time and distance because speed is defined as the distance per unit time and as speed is a scalar quantity it does not have any direction
But for calculating the velocity we require time as well as displacement because velocity is defined as the displacement per unit time and as velocity is a vector quantity it has direction
Displacement is the shortest distance between the initial position and the final position and it has a specified direction as well
There are two kinds of analysis: qualitative and quantitative
In quantitative we analyse the amount of something that is how much of something is present / the quantity. Ex: the length of branch of tree, number of students in class, volume of a liquid in a beaker.
In qualitative analysis we determine the kind of substance / quality of substance / nature of substance.
like: colour of a substance, odor of a substance or taste (bitter / sour / sweet etc) of a substance
So answer is : B.The substance tastes bitter
There are two terms
a) accuracy : it relates to the exactness of an answer that how an answer is close to the actual answer or actual reading
So 104.6 is accurate
b) Precision : This is related to the closeness of different readings with each other
The first reading is 103.7 and the second one is 108.4 so the second reading is quite different from the first reading so it cannot be called as precised
Again 105.8 has good difference from the second reading hence again this is not precised
However the last reading 104.6 is quite near to 105.8 so 104.6 can be called as precise
4 protons are there in the atom