Answer:
a quantitative observation implies that the subject can be measured by quantity, aka amount or in numbers.
Ex 1: adding one gram of salt to one gram of sugar makes two grams of seasoning. in this example, there are individual quantities (1 gram of each) and total quantity (2 grams). this only changes if the substances have a chemical reaction, such as one of them destroying the other, then the weight would change.
Ex 2: a more simple example is the weight of something. putting the substance on a scale (one specifically for whatever you are measuring, whether it be liquid or solid) is the best way to determine its quantity.
Answer:
B. materials change their properties.
Explanation:
In a chemical change, materials often change their properties because a re-arrangement of atoms takes place.
A chemical change is one in which new kind of matter is formed.
It is always accompanied by energy changes.
- Chemical changes are not reversible.
- They lead to the production of new kinds of matter
- It involves mass changes
- Requires considerable amount of energy
Answer: 104 KJ mol
Each NH3 has 3 N-H bonds
Explanation:
Enthalpy change(DHo)= sum t enthalpy of products - sum of enthalpy of Reactants
DHo= 2x3 dHo (N-H) - {dHo(N2)+3dHo(H-H)}
= 6(391)-(945+3(432))
=2346-(945+1296)
=2346-2241
DHo= 105 KJ/mole
True
According to the molecular theory. The average kinetic energy of a gas particle is directly proportional to the temperature. An increase in temperature increases the speed in which the gas molecules move. All gases at a given temperature have the same average kinetic energy.