User:FELIX SARFO

Date: 23th February, 2024. Title: an experiment to determine the density of water. Aim/purpose: to determining the density of water. Apparatus used: electronic balance, distilled water, graduated measuring cylinder, beaker, wash bottle.

Method/Procedure We measure the mass of the empty graduated cylinder on the electronic balance and record the mass as M1 (100.21g) We then Poured a known volume of water into a graduated cylinder where we read the meniscus at eye level for accurate volume measurement. The volume (V) was 51cm3 We use a balance to measure the mass of the empty graduated measuring cylinder with water as M2 (149.72g). We calculated the density of water using the formula, Density (ρ) = (mass of water)/(volume of water)

Observation: It was observed that water is a liquid at room temperature and forms a meniscus in a graduated cylinder. Again, it was also observed that, water has a density of 0.971g/cm3 that is approximately 1g/cm3 Theory Density is defined as the amount of mass present in the unit volume of the given substance. Density (ρ) = (mass of water)/(volume of water) Mass of water = mass of measuring cylinder containing water – mass of empty cylinder. Calculation Mass of empty measuring cylinder (M1) = 100.21g Mass of measuring cylinder containing water (M2) = 149.72g Mass of water = mass of measuring cylinder containing water – mass of empty cylinder. M2 - M1 Mass of water = 149.72g – 100.21g Mass of water = 49.51g Volume of water = 51cm3 Density (ρ) = (mass of water)/(volume of water) Density (ρ) = 49.51g/( 51cm3) Density (ρ) = 0.971g/cm3

Discussion To determine the density of water, we measure the mass and volume of a given amount of water. The formula for density (ρ) is density = mass / volume. For water, at standard temperature and pressure (STP), its density is about 1 gram per cubic centimeter (g/cm³) or 1000 kilograms per cubic meter (kg/m³). we used methods such as a graduated cylinder and a scale to measure volume and mass respectively. Then, we divide the mass by the volume to calculate the density.

Precautions We see to it that the electronic balance was free from air resistance. The graduated cylinder was empty and dried before taking the mass M1. The volume of the water was taking at the meniscus at the eye level. We ensured that the digital balance was at zero reading before measuring the taking the masses to reduce parallax error. Correct apparatus was used to carry out the experiment. Sources of error Measurement Errors: Errors in measuring the volume and mass of the water sample can significantly affect the accuracy of the density calculation. Reading the meniscus incorrectly, inaccuracies in the balance, and errors in pouring or transferring the water can contribute to measurement errors. Contaminants: Impurities or foreign substances in the water sample can alter its density. Ensure that the water used is pure and free from contaminants. Parallax Error: When reading the volume on a graduated cylinder, parallax error, caused by viewing the measurement from an angle, can lead to inaccuracies. Uncertainty in Equipment: The precision and accuracy of the measuring instruments used, such as the balance and graduated cylinder, contribute to overall measurement uncertainty.

Determining error Error = Experimental value – accepted value Error = 1.0g/cm3 – 0.971g/ cm3 Error = 0.029 g/ cm3 percentage error

percentage error = (Experimental value – accepted value)/(accepted value)×100% percentage error = (1.0-0.971)/1.0×100% percentage error = 2.9% Conclusion In conclusion the accepted density of water at standard conditions is approximately 1g/cm3. The experimental value 0.971g/ cm3 is slightly lower than the accepted value due to error occurred during the experiment