Chemistry: Measurements And Significant Figures

To calculate the percentage of Cu, we divided the final mass of the penny 0.09 and the initial mass of 2.47 and multiplied by 100. To calculate the percentage of Zn, we divided the final mass of the penny 2.38 and the initial mass of 2.47 and multiplied by 100. During the experiment the hydrochloric acid donated its hydrogen ions in the reaction and then the chloride ions reacted with the zinc ions in the solution. Thus, the zinc dissolved in the highly acidic solution which was caused by the high concentration of H2 ions. Hydrogen gas was generated during the reaction which was seen when bubbles were formed as the penny was dissolved into the beaker.

The specific heat of three elements were tested zinc, copper, and lead. The experiments ran from Monday to Thursday and allowed a precise amount of heat to be determined. The experiment had multiple errors which were caused by random errors not systematically errors. In order to combat this, certain items were kept same. This was called a control.

In the lab “All That Glitters” the objective that was focused on during the lab was calculating the density, volume and mass of various substances. The method that was used in finding the volume of the samples is called the displacement method. This is a process where the volume of the water in the graduated cylinder is calculated before and after the sample is placed. In this lab, the goal of the experiment was to identify and come to consensus about what the unknown substance might be. For this experiment, the required materials were ten pre and post pennies, unknown sample, graduated cylinder, weigh boat, water, paper towels and a weighing scale.

In almost every experiment, there’s an independent and dependent variable, a constant, and a control group. The independent variable in this lab was the coins. The dependent variable was the density. The constant was the amount of water. In this lab, there was no control group .

If we were given a random sample of pennies, then we could measure the mass and the volume of the pennies. From these measured values we could calculate the density. Then we could compare our calculated density to the given density value of copper and we could find the the percentage of error between copper and the measured density. Conclusion: If the percentage of error between the copper and the measured density of the pennies was large and the values were not in comparison to the density of copper, then we would know that the density of a penny is not the same as the density of pure copper.

In this experiment, the evolution of the copper cycle was observed through a series of reactions. Four different copper compounds are formed through different reactions to inevitably lead to the recovery of Cu(s). This primary goal of this experiment was to study the Law of Conservation of Mass and perform 5 reactions on copper compounds. As Jenna Winterberg states in her book “Conservation of Mass,” the first part of this law is that mass or matter cannot be created. The second part of the law is that mass or matter cannot be destroyed .

I. Purpose: To experimentally determine the mass and the mole content of a measured sample. II. Materials: The materials used in this experiment a 50-mL beaker, 12 samples, a balance and paper towels. III.

The purpose of this lab was to change pennies from copper to silver to gold, like alchemists have attempted to do in history. Through the data and observations gathered throughout this experiment, it can be concluded that the pennies were not changed into a different element. For example, the density of the penny from 2005; which was the penny that was experimented on to see whether or not it could turn into silver; was 4.62 g/cm3 before the experiment and 4.89 g/cm3 by the end of the experiment. If this copper penny really would have turned into silver, then the density of the penny would be 10.49 g/cm3; which is the density of silver; by the end of the experiment. The penny may have turned silver in color, but this was only because it was plated in the zinc that was added to the beaker of water in the experiment.

In this lab there were five different stations. For the first station we had to determine an unknown mass and the percent difference. To find the unknown mass we set up the equation Fleft*dleft = Fright*dright. We then substituted in the values (26.05 N * 41cm = 34cm * x N) and solved for Fright to get (320.5g). To determine the percent difference we used the formula Abs[((Value 1 - Value 2) / average of 1 & 2) * 100], substituted the values (Abs[((320.5 - 315.8) /

On our paper we predicted the amount of pennies that could fit in the boat before it sank. We tested the boat in the water and added pennies one by one. We then calculated the mass of pennies that fit in the boat and the density of it. The purpose of this Lab was to make a boat that holds as many pennies as possible and understand how to calculate

Introduction: The purpose of this experiment is to demonstrate the different types of chemical reactions, those including Copper. There are different types of chemical reactions. A double displacement reaction is a chemical process involving the exchange of bonds between two reacting chemical species. A a decomposition reaction is the separation of a chemical compound into elements or simpler compounds and the single-displacement reaction is a type of

3. In this experiment, the percent yield was 90%. This number implies that there was little error in this experiment. However, this result could have been caused by certain external factors.

Throughout the experiment, copper was altered a total of 5 times, but after the final chemical reaction, solid, elemental copper returned. Each time the solution changed color, a precipitate formed, or when gas appeared, indicated that a chemical reaction was occurring. For the first reaction, copper was added to nitric acid, forming the aqueous copper (II) nitrate (where the copper went), along with liquid water, and

When you multiply or divide measurements, the number of significant figures in the answer is equal to the number of significant figures in the least precise measurement. For the addition or subtraction of measurements, the number of significant figures in the answer is equal to the number of decimal places in the least precise measurement. Nonzero integers always count as significant figures, and exact numbers, quantities obtained without the use of a measuring device, have an infinite number of significant figures. For example, the number 15.1 has three significant figures because none of the integers are zero. However, there are three classes of zeros: leading zeros, captive zeros, and trailing zeros.

In this experiment, the amount of water lost in the 0.99 gram sample of hydrated salt was 0.35 grams, meaning that 35.4% of the salt’s mass was water. The unknown salt’s percent water is closest to that of Copper (II) Sulfate Pentahydrate, or CuSO4 ⋅ 5H2O. The percent error from the accepted percent water in CuSO4 ⋅ 5H2O is 1.67%, since the calculated value came out to be 0.6 less than the accepted value of 36.0%.This lab may have had some issues or sources of error, including the possibility of insufficient heating, meaning that some water may not have evaporated, that the scale was uncalibrated, or that the evaporating dish was still hot while being measured. This would have resulted in convection currents pushing up on the plate and making it seem lighter by lifting it up