8) The vessel to be weighed should be placed of the pan. (off to the side, or in the center) 9) After heating a sample in a dish it will save time to weigh it immediately or cool it completely? 10) To avoid the errors in mass due to the use of balances that are not calibrated, one should weigh by a method called

When large pieces of a purple-black crystalline solid are gently heated, a purple vapor is formed which upon cooling deposits many tiny purple-black crystals with the same hardness, density, reflectivity, etc. as the large pieces.  Did this experiment study chemical changes or physical ones?  Justify your answer with reasoning.

Pls do fast and i will rate instantly for sure Solution must be in typed form  Please show work on these questions. I am having a hard time understanding these concepts.

When calculating the percent error how do I know how many digits should be in my final answer can you give me a example? Can you provide me with example explaining the rule?

We are doing an experiment on measuring the temperature. We are to measure the temperature of hot water (measure it initially, then wait for 10 minutes then measure again). Additionally, we are to measure the temperature of another water before and after putting ice (measure initially then measure 3 times [every 5 minutes] for 15 minutes). My question are: What law or principles of chemistry could be applied in this experiment? Should we expect the temperature of the hot water to drop? why? Should we expect the temperature of the water to rise or drop after putting the ice? why?

I'm not sure how to do this  number 8

A. Characteristics of Elements, Compounds, and Mixtures 1. Complete the table: Color Luster Element Physical State iron sulfur mercury magnesium

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