However the study had low ecological validity as it was not representative of everyday memory demands. Trigrams are meaningfulness information and so may be remembered less well than meaningful information showing that the Peterson and Peterson study lacked mundane realism. STM and LTM also differ in terms of capacity, psychologists believe that LTM has potentially unlimited capacity. The capacity of STM, however, has a very limited capacity. George Miller (1956) concluded that the span of immediate memory is 5-9 items.
And according to our data, our actual yield is 0.5g CaCO3. Thus, our percent yield is 73.5%. Our percent yield was close to 100%, but not very close. I believe the error lies in human error, as well as instrumentation sensitivity. Our scale only measures to grams accurately, and could have not accurately represented the .68g of CaCO3, or we could have lost the solid precipitate in the process of the experiment.
Systematic error in physical sciences commonly occurs with the measuring instrument having a zero error. A zero error is when the initial value shown by the measuring instrument is a non-zero value when it should be zero.1 Systematic error can be caused by various factors that constantly occur which is why they are difficult to steer clear of. The purpose of this experiment is to get acquainted with the effects of systematic errors and the different natures in which they exist leading to the inability to negate errors or losses for further reference future labs. Reagents |Compund |M.W |Amt. Used |B.P/M.P |Density |Structure | |Cyclohexane |84.16amu |“25ml” |80.74° C |0.779g/mL (l) |[pic]2 | |Benzoic Acid |122.12amu |1.00g |250°C |1.27g/ml |[pic]3 | Procedure/Observations 1.)
How do you go from calculated/measured values to accomplishing stated purpose? (4 pts) The purpose of this lab is to determine the exact concentration of an unknown acetic acid solution. Titrations for two different reactions will be performed. Controlled volumes of one reagent are added to a flask containing the other reagent until the equivalence point of the reaction is reached, one between sodium hydroxide (NaOH) and potassium hydrogen phthalate (KHP) and the other between NaOH and acetic acid (CH3COOH). NaOH (aq) + KHP (aq) —› Na+ (aq) + K + (aq) + P2- (aq) + H2O (l) NaOH (aq) + CH3COOH (aq) —› Na+ (aq) + CH3COO- (aq) + H2O (l) The titration of NaOH with KHP will identify the concentration of the NaOH provided.
The smallest relative difference that is not statistically significant is stress management at -0.63. The reason that this ratio is not statistically significant is because the value used to determine significance was lower than 0.05. The smaller t ratio has an increased p value and the odds of being able to reject the null hypothesis are diminished. This result means
Comparing and Contrasting: Compare the ratio of moles of iron to moles of copper from the balanced chemical equation to the mole ratio calculated using your data. 8. Evaluating Results: Use the balanced chemical equation to calculate the mass of copper that should have been produced from the sample of iron you used. Use this number and the mass of copper you actually obtained to calculate the percent yield. 9.
The research suggests that capacity of short term memory could only be enlarged by grouping items together known as chunking. By chunking information, we are more likely able to remember it whether in single or combined forms which is why it’s known as the magical number seven plus or minus two. However, the experiment could also be criticised in the sense that there could have been experimenter bias and demand characteristics. It also isn’t ecologically valid since people don’t have to memorise random letter and numbers all the time. Nevertheless,
10/4/2011 VHS Block 2 Shoe Size and Height Questions 1. While doing this study, there could have been a couple of experimental errors. I could have accidently not produced a 100% accurate measurement for my shoe size, foot size, or height. The reasoning behind this is because since the ruler was not flexible to bend to the shape of my foot or rounded the end of my toe and heal, I had to eye ball the exact measurement. This being said, there was definitely room for some sort, although small, measurement reading error.
Experimental Design: - Independent Variable: different types of metals: magnesium, zinc and Copper - Dependent Variable: amount of reactants observed for each metal - Control : The Air -Constants: The amount of chemical solutions, the time the metals were in the chemical solutions and size of each metal during the experiment 4. The Dependent variable, the number of reactions the metal will receive and will be measured based on their reactivity. The higher the reactant, the more reactions and the less reactive the less amount of reactions The Independent variable, the different metals that are tested by observing for chemical change. Once the metals which are magnesium, copper and zinc are put into the 3 different solutions along with the control which is water and air, we will be able to determine if they do
The percent error is much higher for the first order stopping potential than for the second. This may be due to the fact that the lamp was not fully heated when the measurements were taken. There was not a gauge anywhere to tell when the lamp was fully heated, so it was more of a guessing game than anything. Another source of error may have been the ambient light in the lab. This may have entered the detector during the experiment, skewing the data.