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pochemuha
3 years ago
7

Which is a true statement about Dmitri Mendeleev?

Chemistry
1 answer:
yawa3891 [41]3 years ago
8 0

Answer: The correct answer is option (A).

Explanation:

  • Dmitri Mendeleev published periodic table in 1869.
  • In his periodic table he arranged the elements in the increasing order of their atomic mass.
  • His periodic table consist total 63 elements.
  • He grouped the element on the basis of similarity of chemical and physical properties of the elements.

Hence, the correct answer is option (A)

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Water's heat of fusion is 80. cal/g , its specific heat is 1.0calg⋅∘C, and its heat of vaporization is 540 cal/g . A canister is
Pani-rosa [81]
<span>294400 cal The heating of the water will have 3 phases 1. Melting of the ice, the temperature will remain constant at 0 degrees C 2. Heating of water to boiling, the temperature will rise 3. Boiling of water, temperature will remain constant at 100 degrees C So, let's see how many cal are needed for each phase. We start with 320 g of ice and 100 g of liquid, both at 0 degrees C. We can ignore the liquid and focus on the ice only. To convert from the solid to the liquid, we need to add the heat of fusion for each gram. So multiply the amount of ice we have by the heat of fusion. 80 cal/g * 320 g = 25600 cal Now we have 320 g of ice that's been melted into water and the 100 g of water we started with, resulting in 320 + 100 = 420 g of water at 0 degrees C. We need to heat that water to 100 degrees C 420 * 100 = 42000 cal Finally, we have 420 g of water at the boiling point. We now need to pump in an additional 540 cal/g to boil it all away. 420 g * 540 cal/g = 226800 cal So the total number of cal used is 25600 cal + 42000 cal + 226800 cal = 294400 cal</span>
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3 years ago
What are two benefits of scientists using a diagram to model the water cycle?
tatiyna
I believe that the answer is A i could be wrong though.
5 0
3 years ago
"Nucleic acid was isolated by lysing cells in detergent, guanidine isothiocyanate, and DNAse, followed by extraction in an acid
Romashka [77]

Answer:

RNA

Explanation:

The nucleic isolated was quantified by 2 types of fluorescent dyes, which binds only to specific type of nucleic acid. You can find the information on the specificity of dyes on your labsheet or dye supplier's website. For our dyes, however:

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With these information, we know that our nucleic acid is either single strand DNA or RNA, however, it is also mentioned that

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DNAse, which is an enzyme that breaks down DNA, destroys any extracted DNA during the process, thus, the only possible nucleic acid we have isolated is RNA

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4 years ago
List three harmful effects of excessive nitrates in the environment​
jek_recluse [69]

Answer:

higher costs, energy use and carbon emissions

Explanation:

not sure if this is right or not, I apologize if this is wrong

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3 years ago
Which statement about the periodic table is true?
dedylja [7]

Answer

Two different elements have similar chemical properties when they have the same number of valence electrons in their outermost energy level. ... Elements in the same column of the Periodic Table have the same number of valence electrons – that's why they have similar chemical properties.

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