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sammy [17]
3 years ago
9

What organisms appeared on Earth First?

Chemistry
1 answer:
dusya [7]3 years ago
5 0
It is B because horn coals are bigger and I read it in a book
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Consider the following reaction between calcium oxide and carbon dioxide: CaO(s)+CO2(g)→CaCO3(s) A chemist allows 14.4 g of CaO
sweet-ann [11.9K]

Answer:

Theoretical yield =26.03 g

Percent yield = 87%

Limiting reactant = CaO

Explanation:

Given data:

Mass of CaO = 14.4 g

Mass of CO₂ = 13.8 g

Actual yield of CaCO₃ = 22.6 g

Theoretical yield = ?

Percent yield = ?

Limiting reactant = ?

Solution:

Chemical equation:

CaO + CO₂   → CaCO₃

Number of moles of CaO:

Number of moles  = Mass /molar mass

Number of moles = 14.4 g / 56.1 g/mol

Number of moles  = 0.26 mol

Number of moles of CO₂:

Number of moles = Mass /molar mass

Number of moles = 13.8 g / 44 g/mol

Number of moles = 0.31 mol

Now we will compare the moles of CO₂ and CaO with CaCO₃ .

                  CO₂         :                CaCO₃  

                  1               :                 1

                 0.31           :              0.31

                CaO           :               CaCO₃  

                 1                :                 1

                 0.26         :              0.26

The number of moles of  CaCO₃ produced by CaO are less it will be limiting reactant.

Mass of CaCO₃: Theoretical yield

Mass of CaCO₃ = moles × molar mass

Mass of CaCO₃ =0.26 mol × 100.1 g/mol

Mass of CaCO₃ =  26.03 g

Percent yield:

Percent yield = actual yield / theoretical yield × 100

Percent yield = 22.6 g/ 26.03 g × 100

Percent yield = 0.87× 100

Percent yield = 87%

Limiting reactant:

The number of moles of  CaCO₃ produced by CaO are less it will be limiting reactant.

7 0
3 years ago
5. __NH3 + __O2 >>>>>__ NO +__ H20
inn [45]
2 NH3+ 2 O2 —> 2 NO+ 3 H2O
5 0
3 years ago
Student perfotms a Benedict's test on an unknown substance. He adds reagent(the chemical required to make a color change), and n
elixir [45]

Answer:

Reducing sugars are absent

Explanation:

Benedict's solution is an substance used in testing sugars. It is mixture of sodium carbonate, sodium citrate and copper(II) sulfate pentahydrate. It can be used instead of Fehling's solution in testing for the presence of reducing sugars.

Reducing sugars contain the -CHO group. If there is no colour change after the addition of Benedict's solution, then we can conclude that reducing sugars are absent.

7 0
3 years ago
If the patient has to be administered a dosage of 2 tablets every 8 hours for 7 days, what is the number of tablets required for
Lilit [14]
If the patient has to take 2 tablets every 8 hours for 7 days.
 24/8=3     3*2=6
this means that he patient will have to take 6 tablets every day. 
6*7=42   And the patient must take 42 tablets in all 7 days
Hope this helps! :)
6 0
3 years ago
What are the two main reasons why most metals are more dense than most plastic and wood?
Viktor [21]

Answer:

Most common metals like aluminum, copper, and iron are denser than wood. The atoms that makeup metals are generally heavier than the atoms in plastic and wood and they are packed closer together.

3 0
3 years ago
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