The question is incomplete:
Complete question is
The most efficient way to determine whether a reaction is an exothermic chemical
reaction is to use —
A) an oxygen probe
B) a temperature probe
C) a pressure probe
D) a pH probe
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Answer:
Reaction is said to be exothermic in nature, if heat is evolved from the system. The resultant product formed is more stable. Since, during exothermic reaction, heat is given out be the system, temperature of system will increase. Hence, temperature is the probe to determine exothermic reaction.
Thus, correct answer is option B) a temperature probe
Answer:
(b) BeF2 > OF2 > CH3OH
Explanation:
The degree and type of intermolecular forces present in a substance influences its vapour pressure considerably. The greater the magnitude and strength of intermolecular forces in the substance, the lower the vapour pressure of the substance.
BeF2 molecules are held together by weak vanderwaals forces hence BeF2 will exhibit the least degree of intermolecular interaction and have the highest vapour pressure. OF2 molecules are bound together by dipole interactions hence it will exhibit a lower vapour pressure compared to BeF2. CH3OH molecules form hydrogen bonds with water molecules hence it will exhibit the least vapour pressure among the trio.
When a metal undergoes a reaction, especially with a nonmetal, you should look for the formation of salts or the formation of precipitates in the case the product is not soluble to water. Metals loses electrons to form positive ions which then reacts to nonmetals that are negatively charged ions.<span />
Answer:
(a) dew condensing on a leaf
(c) ice cream melting
Explanation:
The process which can be reversed by changing the temperature , i.e. , by increasing or decreasing the temperature , is called the <u>reversible process</u> .
From the question ,
- dew condensing on a leaf is a reversible process ,
As the water on the leaf can be changed to gaseous state by increasing the temperature .
The process of condensation and evaporation are reversible of each other .
The melted ice cream can be solidified again by reducing its temperature , hence , it is a reversible process .
- an egg turning hard when boiled and the batter cooking on a hot griddle
They both are irreversible process , and by changing the temperature , we can not get back the original substance .
I think it’s A. Hope this helps
