Part A: Four students are taking the general chemistry lab this quarter. Their n
ID: 889841 • Letter: P
Question
Part A:
Four students are taking the general chemistry lab this quarter. Their names are Kemmi Major, Doc Inmaking, Stu Dent, and Noke Lew. They exhibit a range of abilities in the laboratory.
While practicing weighing by differences the students miss steps or do a step incorrectly. Read each scenario in the next four questions, decide which steps were missed or messed up, and classify the resulting error.
Noke Lew weighs an empty beaker. Then she gets a weighboat and transfers the chemical into it. She weighs the weighboat and chemical together, and then pours the chemical into the beaker. Afterwards she carries on with the experimental work. (Hint: select 2 missed steps and 1 classification.)
Step 1. Weight an empty weighboat.
Step 2. Transfer the chemical to the weighboat.
Step 3. Weigh the weighboat and chemical together.
Step 4. Transfer the chemical to a beaker.
Step 5. Weigh the weighboat and chemical residue.
Major error – the real mass of chemical cannot be determined.
Minor error – the real mass of chemical is only estimated.
No error – the real mass of chemical is still known accurately.
Part B:
Doc Inmaking weighs the empty weighboat. He transfers the chemical into the weighboat, weighs the total mass together, and transfers the chemical to the beaker. Then he carries on with the experiment. (Hint: select 1 missed step and 1 classification.)
Step 1. Weight an empty weighboat.
Step 2. Transfer the chemical to the weighboat.
Step 3. Weigh the weighboat and chemical together.
Step 4. Transfer the chemical to a beaker.
Step 5. Weigh the weighboat and chemical residue.
Major error – the real mass of chemical cannot be determined.
Minor error – the real mass of chemical is only estimated.
No error – the real mass of chemical is still known accurately.
Part C:
Stu Dent weighs the empty weighboat and transfers the chemical into it. He weighs the boat and chemical together. As he transfers the chemical into the beaker some of it falls onto the lab bench. He wipes up the spill, notifies the instructor, and finishes weighing the weighboat and residue. Then he continues the experiment. (Hint: select 1 step that Stu didn't do properly and 1 classification.)
Step 1. Weight an empty weighboat.
Step 2. Transfer the chemical to the weighboat.
Step 3. Weigh the weighboat and chemical together.
Step 4. Transfer the chemical to a beaker.
Step 5. Weigh the weighboat and chemical residue.
Major error – the real mass of chemical cannot be determined.
Minor error – the real mass of chemical is only estimated.
No error – the real mass of chemical is still known accurately.
Part D:
Kemmi Major transfers the chemical to a weighboat, weighs the combined mass, and transfers the chemical to a beaker. She weighs the weigh boat with the chemical residue, and continues with her experiment. (Hint: select 1 missed step and 1 classification.)
Step 1. Weight an empty weighboat.
Step 2. Transfer the chemical to the weighboat.
Step 3. Weigh the weighboat and chemical together.
Step 4. Transfer the chemical to a beaker.
Step 5. Weigh the weighboat and chemical residue.
Major error – the real mass of chemical cannot be determined.
Minor error – the real mass of chemical is only estimated.
No error – the real mass of chemical is still known accurately.
Step 1. Weight an empty weighboat.
Step 2. Transfer the chemical to the weighboat.
Step 3. Weigh the weighboat and chemical together.
Step 4. Transfer the chemical to a beaker.
Step 5. Weigh the weighboat and chemical residue.
Major error – the real mass of chemical cannot be determined.
Minor error – the real mass of chemical is only estimated.
No error – the real mass of chemical is still known accurately.
Explanation / Answer
Noke Lew:
Missed Steps:
Classification:
Doc Inmaking:
Missed step:
Classification:
Stu Dent:
Messed up step:
Classification:
Kemmi Major:
Missed step:
Classification: