• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month
Page
1. 1
1
2. 2
2
3. 3
3
4. 4
4
5. 5
5
6. 6
6
7. 7
7
8. 8
8
9. 9
9

# Analysis of the Nitrogen Content of Lawn Fertiliser

Extracts from this document...

Introduction

CHEMISTRY INVESTIGATION Analysis of the Nitrogen Content of Lawn Fertiliser Research Question: What is the percentage by mass of nitrogen (from the ammonium ion NH4+) in Bunnings Green Up brand of lawn fertilizer compared to the manufacturer's specification of 12.3%? Aim: To determine the percentage by mass of available nitrogen, present as the ammonium ion, in Bunnings Green Up brand of lawn fertiliser, then comparing it with the one specified by the manufacturer. Hypothesis: Since the ammonium ion (NH4+) present in fertilisers is a weak acid, it is hard to obtain an exact end point. Hence, back titration can be used to determine the percentage by mass composition of nitrogen in the fertiliser. To deduce the amount of nitrogen in ammonia, the NH4+ ion is reacted with an excess of NaOH, and the amount of unreacted NaOH found by titration with HCl is used to deduce the amount of NH4+ ion present by subtracting it from the initial amount of NaOH to find the amount that reacted with it. From this, the percentage by mass of nitrogen present in the fertiliser can be found and subsequently compared to the manufacturer's specification. It is hypothesized that the percentage by mass of nitrogen present in the fertiliser will be similar or close to that specified by the manufacturer (12.3%). ...read more.

Middle

reacted = 9.58 � 10-4 mol 4. The mole of ammonium in 20 cm3 aliquot and 250 cm3 using the reaction between ammonium and sodium hydroxide: NH4+(aq) + OH-(aq) --> NH3(g) + H2O(l) Molar ratio for NH4+ to NaOH is 1:1 Therefore, the mol of ammonium would be equal to that of sodium hydroxide: n(NH4+) in 20 cm3 = 9.58 � 10-4 mol n(NH4+) in 250 cm3 = 9.58 � 10-4 � n(NH4+) in 250 ml = 0.011975 mol 5. Find the nitrogen content by mass in ammonium ion (NH4+). Molar ratio for NH4+ to N is 1:1 Therefore, n (N) = 0.011975 mol m(N) in NH4+ = n � Mr (g) of N in NH4+ = 0.011975 � 14 m(N) in NH4+= 0.16765 g 6. The percentage by mass of nitrogen found in fertiliser: % by mass of N = m(N) in the Sample x 100 Sample mass % by mass of N = � 100% % by mass of N = 13.87% � 1.00% found in the sample Bunnings Green Up fertiliser The difference between the theoretical value (manufacturer's specification) and the experimentally found value: 13.87% - 12.3% = 1.57% The percentage uncertainty: � 100 = 7.21% The percentage difference: � 100 = 12.76% Since the % difference is greater than the % uncertainty, it is suggested that systematic errors are present in this investigation. ...read more.

Conclusion

This may be overcome by using another indicator that allows for a clearer colour contrast. Another possible limitation which may have impacted the results is that some ammonia may still have been present in the conical flask. Although the red litmus paper may have served its purpose, this may still occur as a result of not boiling the solution long enough and thus some ammonia may not have evaporated. The result of this is that the ammonia in the solution will react with the hydrochloric acid, and therefore more hydrochloric acid will be required for the equivalence point to be reached, affecting the titre volume. This can be easily overcome by ensuring that the fertiliser solution containing water and sodium hydroxide is boiled for long enough so that all ammonia can evaporate, while simultaneously ensuring that the solution remains at a constant 90mL. The use of tap water may also have affected the results. It may not have been at a pH of 7 or may contain other contaminants such as salts which may ultimately interfere with the results. To overcome this, the most effective way is to use deionised water. Conclusion: It was found that the percentage by mass of nitrogen from the ammonium ion in Bunnings Green Up brand of lawn fertilizer was 13.9% (? 1.00%). This was very close to the percentage of nitrogen in lawn fertiliser as specified by the manufacturer ? 12.3%. ...read more.

The above preview is unformatted text

This student written piece of work is one of many that can be found in our International Baccalaureate Chemistry section.

## Found what you're looking for?

• Start learning 29% faster today
• 150,000+ documents available
• Just £6.99 a month

Not the one? Search for your essay title...
• Join over 1.2 million students every month
• Accelerate your learning by 29%
• Unlimited access from just £6.99 per month

# Related International Baccalaureate Chemistry essays

1. ## Airbag design lab. Is it possible to use baking soda, NaHCO3(s), and 2.00 ...

PV/RT=n (99.18)(.734732L)/(8.314)(293k)=n �0.02991406 mol-1 Mass of Baking Soda (NaHCO3) m=(n)Mr 0.02991406 mol-1 x 84.0059 g/mol-1 =2.5129579g �2.5130 g Conclusion: The following execution of the experiment proved that it is possible to construct an effective airbag out of hydrochloric acid and baking soda. The following was done in the experiment.

2. ## Acids/Bases Design Lab. How does a change in the pH value of a solution ...

The temperature of the hydrochloric acid solution should be at room temperature, as should the zinc metal strips being used in the investigation. The zinc metal strips, once exposed to the room temperature air, will adjust themselves to conform to the atmospheric temperature, and can do so as the investigator is setting up their materials.

1. ## Enthalpy Change Design Lab (6/6)How does changing the initial temperature (19C, 25C, 35C, and ...

and HCl(aq) solutions in the 150 cm3 beaker will be monitored using Vernier temperature probes, connected to a Vernier LabQuest with DataLogger Pro collection software so that they are reacted when both reach the same temperature. [Note: A temperature of 19�C was selected as one of the lower variations because of the following reasons.

2. ## The purpose of this Titration Analysis of ASA experiment was to use titration analysis ...

Calculations In order to calculate the concentration of NaOH(aq), we must first find the concentration of KHP. - Uncertainties Used For Calculations: - Volumetric Flask: �0.8ml used for preparing the standard solution. - Electronic Mass Scale: �0.01g used in measuring the amount of KHP needed.

1. ## Biodiesel Investigation - How the concentration of Potassium Hydroxide solution would affect the yield ...

1 The diagram on the left shows the transesterification process that forms two products (Glycerol and A 3-methyl ester). The experiment conducted involves potassium hydroxide as a catalyst instead of sodium hydroxide. Furthermore the biodiesel product of this varies from the other structured methyl ester that usually come in The other product is glycerol, which is commonly found in soaps.

2. ## Chemistry Titration Acid Base Lab

The table below represents how temperature can affect the pH range for a color change for specific indicators. To ensure this does not occur, the lab should be taken out in a room with no windows so the temperature does not change.

1. ## Measuring the fatty acid percentage of the reused sunflower oil after numerous times of ...

after its first use, making it useless. And the oil begins to breakdown creating acrolein (systematic name: propenal) which is the simplest unsaturated aldehyde as an obnoxious-smelling compound. Thus oil has to have a high smoke point If it is going to be used many times.

2. ## The purpose of this experiment is to determine the concentration of a solution of ...

If % difference is greater than experimental errors then there are systematic errors in the procedure. Several trends were observed from the qualitative and quantitative observation :- 1. The solution got its fade pink color between when 25ml-26ml of burette solution was titrated.

• Over 160,000 pieces
of student written work
• Annotated by
experienced teachers
• Ideas and feedback to