a. Exothermic process. Heat is released as it feels hot when one stands near it.

b. Endothermic process. Water absorbs heat from body to evaporate from the skin.

c. Endothermic process. Ice absorbs heat energy from the environment to break the intermolecular bonds in order for it to melt.

Explosion happens when the reactant being a solid turns into gas as the product through a reaction. This gas produced cause a sudden increase in volume which in turn becomes an explosion.
In order for there to be a good explosion, the product must have relatively low energy so that it is more stable than the reactant. Therefore, the reactant will have to have relatively weak bond strength as compared to the product.

Temperature is a quantitative measurement of heat present in the surroundings while heat is a form of internal energy that is felt by oneself.
An example is when you feel that the air is hot, which is the amount of heat present, but the temperature is not very high.

a. Gasoline has 98% isooctane and 2% heptane.

b. Octane rating is the ratio for the comparison with a standard for the fuel but there is no part in the ratio that refers to oxygenates. If one wants to know if the fuel contains oxygenates, more analysis has to be done or to contact the supplier about it.

A . Exothermic , Burning of coal results in releasing energy
B. Endothermic , Water molecules must absorb heat from the surrounding to evaporate , hence causes us to feel cool when water evaporates from our skin.
C. Endothermic , By absorbing heat from the atmosphere to melt. When ice melts at room temperature , it absorbs energy from the surroundings air but not at the Arctic where temperature is less than 0 degrees.

When relative bond strengths of the reactants are less than the relative bond strengths of the products , it would cause the net energy to be more than 0. Exothermic reactions releases heat whereby the bond difference must be tremendous and huge such that ab explosion would occur.
The greater the bond energy difference , the stronger the explosion where if the energy difference is negative , the explosion would be stronger.

In a cold bathroom , running hot water the bath temperature is at 42 degrees. Tthis causes the whole bathroom to be humid and steamed up. This is illustrated as heat.

However in a cold bathroom , where a beaker of water would just be boiled at 100 degrees would be denoted as temperature.

Heat is transfer of energy while Temperature is measuring how fast the particles in a substance are moving.
Hence by touching a hot cup of water , we would feel the heat on to our finger tips . However the temperature cannot be felt and changes.

a) 98% isooctane and 2% n- heptane. This gasoline has a high resistance to knocking. The higher the octane rating, the higher the resistance to knocking.

b) It does not tell us if the fuel contains oxygenates.

a) Exothermic – Heat is released
b) Endothermic – Heat it absorbed
c) Endothermic – Heat is absorbed

Reactant have weaker bonds thus less energy is required to react. Product have stronger bonds, therefore gives large amount of energy.

Heat is the total energy of an object while temperature is the average energy for each particle in that object.
Example 1: An iceberg has more heat energy than a cup of boiling water since there are more particles in an iceberg.
Example 2: Temperature of a small cup of water can be the same as he temperature of a large tub of water but the large tub of water contains more molecules thus have more heat energy.

a)Knocking characteristics of 98% isooctane and 2% heptane
b)Not enough information about it.

a) Endo Energy is released.
B) Endo Energy is absorbed to break the intermolecular bonds holding the molecules together.
C) Endo. Energy is absorbed to change the state from solid to liquid.

Bonds forming release energy and breaking of bonds create energy.
In order for a good explosion to occure, the bond strengths of product should be much greater than the bond strength of reactants. So, the reaction would be extremely exothermic.

Heat is the flow of energy(thermal) from a system of higher temperature to system of lower temperature.
Temperature is the measure of internal enegy of an object.

A) It has a higher resistance to cause knocking in a vehicle’s engine. Therefore less prone to preignition.
B) Oxygenates is a form of additives added to fuel to increase the octane rating. The average octane rating of fuel is 87-89. Therefore it is likely that oxygenates are added to increase octane rating.

a) Exothermic, Heat energy is released from the charcoal to cook food thus when standing near charcoal people will feel hot.
b) Endothermic, Water absorbs heat from the skin as it evaporates and thus giving a cool feeling.
c) Endothermic, heat energy is absorbed to break the intermolecular forces as rigid ice becomes slippery liquid.

Since chemical explosions are highly exothermic, Reactants should have a low bond strength and products should have high bond strength. This would lead to negative H and thus an exothermic reaction.

Heat is the amount of energy in a system –> SI units Joules
Temperature is the measure of average molecular movements in a system –> SI unit Kelvin.

Everyday examples,
For temperature, just show your friend the thermometer.
For heat ask him/her to touch a stove.

98 Octane number tells us that it has a knocking characteristic of 98% isooctane and 2% heptane.

It can be assumed that octane number below 100 has no oxygenates as oxygenates are additives used to increase the overall rating of the gasoline.

a. Exothermic- the reaction is a combustion process,in which heat is given out.
b. Endothermic- there is a gain in heat energy to break the bonds in water to form water vapor
c. Endothermic- heat energy is absorbed to break the bonds in the solid state

The bond strength of products are higher than that of the reactants. This results in a greater amount of energy needed to form the bonds. As such, the enthalpy of combustion is higher resulting in an exothermic reaction. Moreover, the products formed should be gases (rapid increase in volume) instead of solids or liquids leading to explosive reactions.

Temperature: is the direction of heat flow and measures the speed at which heat energy flows
Heat: Flow of energy from a hotter to a colder object
Example: A cube of ice placed on the hand of a man. Overtime, heat conducted from the man’s hand to the ice cube will cause it to melt.

a. The premium gasoline is made up 98% isooctane and 2% heptane. This implies that the gasoline has a relatively high octane rating, resulting in lower knocking characteristics.
b. Octane rating is insufficient to determine if the fuel contains oxygenates.

a) A charcoal briquette burns: exothermic because combustion has occurred resulting in heat radiating out

b) Water evaporates from your skin: endothermic because when water evaporates it changes from liquid to gaseous state and in the process energy is absorbed

c) Ice melts: endothermic because energy is absorbed when ice turns from solid to liquid state

Bond strength for the reactants has to be higher than the bond strength of products.
Bond energy (products) – bond energy (reactants) <0 for exothermic reactions
Therefore more energy is required to break the bonds for the reactants.

Heat exist in the form of energy while temperature is a measurement for it.
eg. Putting hot metal into cold water illustrates energy transfer where the hot metal will cool down while the water will heat up

a) The premium gasoline has octane rating of 98 where 98% is isooctane and 2% is heptane.

b) We cannot tell if the fuel contains oxygenates as the octane rating is only a ratio of hydrocarbon

a) A charcoal briquette burns: exothermic because combustion has occurred resulting in heat radiating out

b) Water evaporates from your skin: endothermic because when water evaporates it changes from liquid to gaseous state and in the process energy is absorbed

c) Ice melts: endothermic because energy is absorbed when ice turns from solid to liquid state

Bond strength for the reactants has to be higher than the bond strength of products.
Bond energy (products) – bond energy (reactants) <0 for exothermic reactions
Therefore more energy is required to break the bonds for the reactants.

Heat exist in the form of energy while temperature is a measurement for it.
eg. Putting hot metal into cold water illustrates energy transfer where the hot metal will cool down while the water will heat up

a) The premium gasoline has octane rating of 98 where 98% is isooctane and 2% is heptane.

b) We cannot tell if the fuel contains oxygenates as the octane rating is only a ratio of hydrocarbon

a) Exothermic: Heat is released during exothermic reactions
b) Endothermic: Heat is absorbed during reaction. Water absorbs heat from the surrounding and from our body temperature which translate into energy for the conversion of liquid to gaseous state.
c) Endothermic: Heat is absorbed during reaction. Ice absorbs heat from surroundings which results in the energy provided for solid to become to liquid.

A good explosion would be more exothermic. For exothermic reactions, the products have a lower energy level than the reactants, therefore bond strength of products is less than bond strength of reactants.

Heat is a form of energy transfer while temperature is the measurement of the amount of heat. Temperature is the direction of the flow of heat. For example, you feel hot because of the heat from the sun, and you can check the temperature with a thermometer.

a) 98% isooctane and 2% heptane
b) Octane rating does not indicate the level of oxygenates in fuel. Oxygenates are usually in gasoline to reduce carbon monoxide.

(a) Exothermic because it gives off heat to the environment
(b) Endothermic because water absorb heat from the skin to get evaporated
(c) Endothermic because ice absorbs heat to melt into liquid state

The bond strength in the product is significantly greater than that of the reactant. This is because for exothermic reaction to occur, ΔH=|Energy of reactants|-|Energy of products|<0
It is also known that energy is released when bonds are formed in the product and energy is needed to break the bond in the reactant side.

Heat is a consequence of motion at the molecular level while temperature is a measure of average of that motion.
Set up an experiment with a cup of hot and cold water respectively. Place one hand on the hot cup from until no heat can be felt. Then, place the other hand on the cold cup to feel the ‘coldness’. This feeling of coldness is due to the flow of heat from the ‘hot’hand to the cold cup.

(a) Knocking characteristic of 98% isoctane and 2% heptane
(b) Fuel does contain oxygenates as oxygenates increases the octane rating of the premium gasoline.