## Friday, January 17, 2020

### Calorimetry Prelab

Experiment 12 Calorimetry and Heat of Reactions ____________________________________________________________________________________________________________ PERFORMANCE GOALS: 1. To learn how to use of a calorimeter 2. To learn how to collect and manipulate data in the computer 3. To calculate the calorimeter constant 4. To use Hess' Law to find the heat or formation of magnesium oxide CHEMICAL OVERVIEW: Ã¢â‚¬ ¢Enthalphy: (? H) : when chemical or physical changes occur at a constant pressure. Ã¢â‚¬ ¢Calorimeter: is an instrument with insulating walls where the reaction happens. Eq. 1: q rxn = -qsurrounding Heat of capacity of the calorimeter: Ã¢â‚¬Å"CpÃ¢â‚¬  must be calculated at the beginning of every calorimeter experiment in Joules/ Ã‚ °C Heat Capacity of the Calorimeter: The calorimeter constant is easily found by adding a fixed amount of hot water to a known amount of cold water and the change in temp for each recorded, due to the Law of Energy Conservation the amount of heat r eleased by the hot water should be equal to the amount of heat absorbed by the cold water: Eq. 2 q released( Hot Water) = -q absorbed (Cold Water) If there is a discrepancy between these two values use the following equation:Eq. 3q= m x spht x ? T Where spht is the specific heat of the substance in J/ gÃ‚ °C ?T is the temperature change in Ã‚ °C andm is the mass in grams Mass of Cold Water|51. 20 g| Initial temperature of cold water|20. 3 Ã‚ °C| Mass of hot water|49. 82 g| Initial temp of hot water|98. 2 Ã‚ °C| Final temp of the mixture|58. 3 Ã‚ °C| Eq. 4qHot = mHot x sphtWater x ? THot qHot = (4. 184 J/ Ã‚ °C-g)(49. 82g)(58. 3 Ã‚ °C-98. 2 Ã‚ °C) = -8317 J Eq. 5qCold = mCold x sphtWater x ? TCold qCold = (4. 184 J/ Ã‚ °C-g)(51. 20g)(58. 3 Ã‚ °C-20. 3 Ã‚ °C) = 8142 J 8317-8142 = 175 joules Cp = ( 175 J ) / (58. Ã‚ °C Ã¢â‚¬â€œ 20. 3 Ã‚ °C) Cp = 4. 6 J/ Ã‚ °C HEAT OF REACTIONS: q released = -q absorbed Eq. 6 q released = Ã¢â‚¬â€œ (q solution + q calorimeter ) Eq. 7 qSolution = mSolutio n x sphtWater x ? TSolution sphtsolution= 4. 184 J/ g Ã‚ °C Eq. 8q calorimeter= Cp x ? T Eq. 9 q reaction = ? Hreaction Hess's Law Hess's Law states that the enthalpy of a reaction is independent of the steps that it takes to get from reactants to products because enthalpy of reaction is a state function. State Function- depends on initial and final state but not on the path taken ?Temperature ?Volume ?Pressure ?Energy Mg (s) + 1/2 O2 (g) Ã¢â‚¬â€œ> MgO ( s) PRE-LAB ASSIGNMENT 1. Predict the product, balance the questions and write the net ionic equations for the reactions: a. Mg (s) + HCI (aq) Ã¢â‚¬â€> b. MgO (s) + HC: (aq) Ã¢â‚¬â€> 2. Write the reaction that represents the enthalpy of formation ( ? Hfor ) of water. 3. Use the table of the thermodynamic data in your text book to calculate the ? H for each of the three reactions REMEMBER Eq. 10 ( ? H Ã‚ °rxn = ? ( n? H Ã‚ °for )prod Ã¢â‚¬â€œ ? ( n? H Ã‚ °for )react 1) 2) 3) 4. Use Hess's Law combining the three molecular equations to calculate the ?Hrxn for the reaction of the formation of MgO. PROCEDURE A. CALIBRATION OF THERMISTOR 1. 2. 3. 4. 5. 6. 7. B. DETERMINATION OF THE HEAT CAPACITY OF THE CALORIMETER 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. C. REACTION OF MgO AND HCI 1. 2. 3. 4. 5. 6. 7. 8. 9. D. REACTION OF Mg AND HCI 1. 2. 3. 4. 5. 6. 7. E. DATA AND CALCULATIONS A. Calorimeter Constant Mass of Styrofoam cup with lid + spin bar (g)|| Mass of cup with lid + spin bar + 50mL of room temp. water (g)|| Initial Temp of Room Temp. Water ( Ã‚ °C )|| Initial Temp of Hot Water( Ã‚ °C )|| Total mass at the end (g)||Calculated Heat released by Hot Water (J) (Eq. 4)|| Calculated Heat absorbed by R. T Water (J) Eq. 5)|| Calculated Heat absorbed by Calorimeter (J)|| Calculated Heat Capacity of the Calorimeter, Cp (J/Ã‚ °C) (Eq. 8) || B. Heat of Reaction of MgO Mass of weighing boat (g)|| Mass of weighing boat + Magnesium oxide (g)|| Mass of Magnesium oxide (g)|| Mass of Styrofoam cup with lid + spin bar (g)|| Mass or Styrof oam cup with lid, spin bar (g) + HCI|| Calculated Mass of HCI (g)|| Total Mass of solution at the end|| Calculated Mass of MgO (g) (using total mass of solution)||Initial Temperature of Solution (Ã‚ °C) (before MgO was added)|| Final. Temp of solution (Ã‚ °C) (after MgO was added)|| Calculated Heat absorbed by solution (J) (Eq. 7)|| Calculated Heat absorbed by calorimeter (J) (Eq. 8)|| Calculated Total heat absorbed|| Calculated Total heat released by the solution (Eq. 6)|| Calculated Moles of MgO|| Calculated Moles of HCI|| Heat released per Mole of MgO|| Molar Heat Reaction (kJ/mol)|| C. Reaction of Mg with HCI Mass of weighing boat (g)|| Mass of weighing boat + Magnesium (g)|| Mass of Magnesium (g)|| Mass of Styrofoam cup with lid + spin bar (g)||Mass or Styrofoam cup with lid, spin bar (g) + HCI|| Calculated Mass of HCI (g)|| Total Mass of solution at the end|| Calculated Mass of Mg (g) (using the final mass of solution)|| Initial Temperature of Solution (Ã‚ °C) (before Mg was a dded)|| Final. Temp of solution (Ã‚ °C) (after Mg was added)|| Calculated Heat absorbed by solution (J) (Eq. 7)|| Calculated Heat absorbed by calorimeter (J) (Eq. 8)|| Calculated Total heat absorbed|| Calculated Total heat released by the solution (Eq. 6)|| Calculated Moles of Mg|| Calculated Moles of HCI|| Heat released per Mole of Mg||

## Thursday, January 9, 2020

### Ethical Relativism Is An Unsound And Unreliable Ethical...

Ethical Relativism is an unsound and unreliable ethical philosophy Mohammed Jweihan Ethics for a Global Economy Ethical Relativism is an unsound and unreliable ethical philosophy Cultural and ethical relativisms are widely used theories that explain differences among cultures and their ethics and morals. Morality deals with individual character and the moral rules that are meant to govern and limit oneÃ¢â‚¬â„¢s character. On the other hand Ethics is somewhat interchangeable with morals, but it actually defines the principles of right conduct, thus to some extent, enlarging its scope to a societal or communal level. Ideally, ethics play a vital role in determining the dos and donÃ¢â‚¬â„¢ts when dealing with the society. This essay will discuss what ethical realism is, analyzing why ethical relativism is unsound and unreliable in relation to the relevant evidence and literature, providing valid reason to ascertain why this is the case. Ethical realism This is a doctrine that bases its arguments in the fact that there are no universal absolute truths in ethics and that what is morally right or wrong varies from person to person or from society to society. Ethical relativism is a similar concept, based specifically on the ethics of a culture and how they are related to those of other cultures (Kluckhohn, 2011). Herodotus, the Greek historian advanced this view when he observed that different societies have different customs and that each person thinks that his customs are

## Sunday, December 15, 2019

### My View on Sporting Event Free Essays

Popular events like the football world cup and other international sporting occasions are essential in easing international tensions and releasing patriotic emotions in a safe way. To what extent do you agree or disagree with this opinion? In present days,more and more countries are putting big sporting events into national agenda due to a sporting explosion and their increasingly attentions towards multinational sports occupations. Meantime,issues are highly debated on whether such international sporting activities can ease the intensive atmospheres between competitive countries or not. We will write a custom essay sample on My View on Sporting Event or any similar topic only for you Order Now Personally, I really appreciate the former idea for several reasons. In general,popular sporting events contribute to harmonious relationships between the participated nations. To start with,communications between nations during the games enable them to be closer to others. Participation in the events promotes the development of friendshios and recongnition,which are acquired by sharing the exciting moments and cooperating with each other. Moreover,every joining country is likely to concentrate on the game during the competiton,which ,as a result,tend to pay less attention to deal with his enemies in the fields of politics or economy. It is true that countries can afford no distraction to pose threats to the security of other countries during the game. Admittedly,sporting events may not function well to shoulder the responsibility for eliminating the contradiction between countries. The reason for this is that such events can make competitions even more intensive than before,provided that one country win another,which is coincidently its enemy. Obviously,the situation tends to be counterproductive,let alone the expectation of an improvement. Even so,it is unusual that such sort of thing happens frequently,as the game launched internationly is seen as a profile of promoting team spirit and paticipation. In summary,I would concede that the sporting events cause worse problems in some cases. Despite that,they play pivotal roles in cooling strained emotions safely. Overall,I am convinced that more and more countries should join in the events. How to cite My View on Sporting Event, Papers