Chemistry: Temperature and Kinetic Energy Essay

Submitted By kamyar240
Words: 1031
Pages: 5

Theory

All things that exist are known as matter and are made of molecules and atoms. The chemical properties of all things are determined by the atoms composition and structure. These two things also affect the physical properties of liquids and solids. How quickly or how often the molecules and atoms move and collide determine the temperature also determining the state of matter and the kinetic energy. The faster they are moving the higher the object’s temperature, the higher the kinetic energy. Kinetic energy is simply the fact that a moving object can do work on anything it comes in contact with.
The formula to find the average kinetic energy at a given temperature is
KE =32KT
There are three phases of matter known as solids, liquids, and gases. The determining factors of the three states are the molecules' and atoms' movement and structure. When a substance is a solid, the atoms in the object are packed together tightly due to strong bonding. The atoms move slower because there is less room to move around. If a substance is a liquid the object is not packed together as tightly and the bonding is not as strong. In a liquid the atoms move around more and at a faster rate than they would in a solid state would. Now if the substance is a gas, the atoms are not packed together tightly, they are loose. The looseness or distance between the atoms allows the atoms to move around more freely and quickly due to lack of a strong intermolecular bond. When enough energy is added or excised a temperature change or phase change may occur, where for instance; if enough energy is removed from a liquid it’s state of matter will transition into a solid phase. Tmelt is the variable of the melting temperature. The heat required to melt a single mole of a solid substance is the molar enthalpy(heat) of fusion also shown as ∆Hfusion . Cp represents the heat capacity of a substance. The melting temperature of a substance is the temperature at which a substance changes from a solid to liquid. In this lab, we are interested in the transition from a solid to a liquid state.
Heat transfer occurs between substances when the energy of one substance is transferred to another. The chemical reaction where a substance absorbs energy(heat) from its surrounding is known as endothermic. A chemical reaction in which energy is released is known as exothermic. The endothermic and exothermic reactions are related to the positive or negative charge of the heat change depending on whether heat is released or absorbed. If the heat absorbed it is positive, when heat is being released it is negative. The energy flows from the warmer object to the cooler object. When the warmer object loses heat, its temperature decreases and when the cooler object receives the heat, its temperature rises. The molecules in the warmer object move faster than the ones in the cooler object. When the warmer and cooler objects come into contact, the faster moving molecules slow down and the slower molecules speed up, eventually they reach the same speed and temperature. The reason this occurs is because when the molecules collide they cancel out each others speed.
The heat capacity of a substance can determine how the object absorb or lose heat. We can measure the amount of heat absorbed or transmitted from an object using the following equation:
Q=nCp∆T
In this equation, the Q represents the heat absorbed or released, n represents the number of moles of the substance , Cp represents the heat capacity and the ∆T represents the change in temperature.
A calorimeter is an insulated tool used to measure the amount of heat released or absorbed during a physical or chemical process. You immerse a substance in a fluid and determine the total amount of heat through the heat flow . When you immerse the substance the heat from the substance surrounded by fluids has nowhere to go except into the fluid. A calorimeter allows us to measure heat…