It gets complicated with the seasons and legnth of days, but as a general rule, about every 21 days from end of heat to the end of the next heat, or beginning of heat to beginning of the next heat. The washing machine does not heat water. It brings hot water in from the hot water heater. They are usually hooked into the same water supply as your shower and sinks.
Yes they generally have a heat element, similar to what's in a kettle. Many washing machines take in cold water only illustrating this ability. Log in. Study now. See Answer. Best Answer. The purpose is to delete any contaminant and to obtain a constant weight.
Study guides. Science 20 cards. Who is known as the first African American scientist. What is Luis Alvarez's cultural background. What was Benjamin Banneker's ethnic background. Which scientist used mathematical knowledge to calculate the exact measurement of the meter.
Genetics 20 cards. What are chromosomes made of. How are mitosis and meiosis similar. What is a gel electrophoresis chamber. In pea plants what are the two alleles for color. You must let the crucible cool before measuring it because the heat from the crucible warms the surrounding air, which rises, then that air cools down and falls. This rise and fall of surrounding air is called a convection current and will give you an unsteady reading that is rising and falling.
These currents will make it hard to find the weight of the anhydrate CuSO4 , thus making it hard to find n , the moles of water per mole of CuSO4. While these are all very good answers, I have a much simpler one. These far overthink the question. The crucible has to cool in the desiccator to avoid adding moisture to it.
The experiment you're doing deals with hydrates, therefore getting as much moisture out as possible is important as it will reduce your percent error. Sign up to join this community. The best answers are voted up and rise to the top.
Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Why is it obligatory to cool down the container of a sample to measure its mass in a lab?
Ask Question. Asked 6 years, 9 months ago. Active 4 years, 2 months ago. Viewed 64k times. When the magnesium has stopped glowing, turn off the Bunsen burner and allow the crucible to cool down. Again, measure and record the total mass of the crucible, its lid and contents.
Results The table shows some example results. Step Mass g Mass of crucible and lid step 1 Mass of crucible and lid step 1. Mass of crucible, lid and magnesium step 3. Mass of crucible, lid and magnesium oxide step 7. AQA Combined science: Synergy 4. Explain any observed changes in mass in non-enclosed systems during a chemical reaction and explain them using the particle model.
AQA Combined science: Trilogy 5. Related articles. Resource Introducing moles numeracy worksheet 14—16 years TZ Five out of five Use the context of cooking to get students more comfortable with concepts such as balanced equations, ratios and reagents. Ideas Stoichiometry and moles: how to explain it? News What is difficult about concentration? Load more articles. You're not signed in.
Only registered users can comment on this article. Sign in Register. More Experiments. Experiment Practical potions microscale 11—14 years TZ Observe chemical changes in this microscale experiment with a spooky twist.
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