Answer: (3)
Medeleev arranged elements in order of increasing atomic weight and similar properties
He noticed that similar elements were grouped together by using this.
Answer:
Weigh the empty crucible, and then weigh into it between 2 g and 3 g of hydrated copper(II) sulphate. Record all weighings accurate to the nearest 0.01 g.
Support the crucible securely in the pipe-clay triangle on the tripod over the Bunsen burner.
Heat the crucible and contents, gently at first, over a medium Bunsen flame, so that the water of crystallisation is driven off steadily. The blue colour of the hydrated compound should gradually fade to the greyish-white of anhydrous copper(II) sulfate. Avoid over-heating, which may cause further decomposition, and stop heating immediately if the colour starts to blacken. If over-heated, toxic or corrosive fumes may be evolved. A total heating time of about 10 minutes should be enough.
Allow the crucible and contents to cool. The tongs may be used to move the hot crucible from the hot pipe-clay triangle onto the heat resistant mat where it should cool more rapidly.
Re-weigh the crucible and contents once cold.
Calculation:
Calculate the molar masses of H2O and CuSO4 (Relative atomic masses: H=1, O=16, S=32, Cu=64)
Calculate the mass of water driven off, and the mass of anhydrous copper(II) sulfate formed in your experiment
Calculate the number of moles of anhydrous copper(II) sulfate formed
Calculate the number of moles of water driven off
Calculate how many moles of water would have been driven off if 1 mole of anhydrous copper(II) sulfate had been formed
Write down the formula for hydrated copper(II) sulfate.
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Explanation:
A risk-benefit analysis compares the risks and benefits of a situation and determines whether the advantages outweigh the disadvantages.
<h3>What is Risk-benefit analysis in technology?</h3>
Strengths
Risk-benefit analysis calculates the amount of time will be worth it to the production of technology and whether the technology will have a healthy impact on the industry or not.
Weaknesses
Risk-benefit analysis cannon determine product implementation and the outcomes of real life experiences of individual customers. It has some drawbacks like benefits of customer is take under consideration but pollution in nature is not calculated.
Implication
Risk-benefit analysis is implied in almost all technical industry as it the decision maker of any developing team to work on a particular project or not. Some examples are automobile industry and smartphone industry.
Learn more about risk-benefit analysis
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Answer:
Only the organisms best adapted to their environment tend to survive and transmit their genetic characters in increasing numbers to succeeding generations while those less adapted tend to be eliminated.
Explanation:
According to Darwin's Theory of Evolution.
Hope this helped.
Volume fraction = volume of the element / volume of the alloy
Volume = density * mass
Base: 100 grams of alloy
mass of tin = 15 grams
mass of lead = 85 grams
volume = mass / density
Volume of tin = 15g / 7.29 g/cm^3 = 2.06 cm^3
Volume of lead = 85 g / 11.27 g/cm^3 = 7.54 cm^3
Volume fraction of tin = 2.06 cm^3 / (2.06 cm^3 + 7.54 cm^3) = 0.215
Volume fraction of lead = 7.54 cm^3 / (2.06 cm^3 + 7.54 cm^3) = 0.785
As you can verify the sum of the two volume fractions equals 1: 0.215 + 0.785 = 1.000
