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Eddi Din [679]
3 years ago
9

A radioactive substance of mass 768g has a half life of 3 years. After how many years does it leave only 6g undecayed?​

Chemistry
2 answers:
vagabundo [1.1K]3 years ago
8 0

Answer:

The answer is 21 years.

Explanation:

7×3

sammy [17]3 years ago
5 0

Answer:

hi

good morning

myself veeresh

and you

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10. How many g of Cu(OH)2 can be made from 9.1 x 1025 atoms of O?
il63 [147K]
Molar mass Cu(OH)₂ = 97.561 g/mol

97.561 g Cu(OH)₂ --------------- 6.02x10²³ atoms
  ? g Cu(OH)₂ -------------------- 9.1x10²⁵ atoms

mass = 9.1x10²⁵ * 97.561 / 6.02x10²³

mass = 8.87x10²⁷ / 6.02x10²³

mass = 14734.2 g

hope this helps!
8 0
3 years ago
8. Which is a nonrenewable resource?
butalik [34]

Answer:

Coal

Explanation:

Once it's all been mined, there's no more. It's not like we grow it.

5 0
3 years ago
Read 2 more answers
Which of the following statements about elements is not true?
guapka [62]

Answer:

Option A is not true

Explanation:

Could you please follow me and mark me as the brainliest answer

6 0
3 years ago
The average propane cylinder for a residential grill holds approximately 18 kg of propane. How much energy (in kJ) is released b
brilliants [131]
Combustion is a chemical reaction between a fuel and an oxidant, oxygen, to give off combustion products and heat. Complete combustion results when all of the fuel is consumed to form carbon dioxide and water, as in the case of a hydrocarbon fuel. Incomplete combustion results when insufficient oxygen reacts with the fuel, forming soot and carbon monoxide. 

The complete combustion of propane proceeds through the following reaction:
C_{3} H_{8} + 5O_{2} --> 3CO_{2} + 4H_{2}O

Combustion is an exothermic reaction, which means that it gives off heat as the reaction proceeds. For the complete combustion of propane, the heat of combustion is (-)2220 kJ/mole, where the minus sign indicates that the reaction is exothermic. 

The molar mass of propane is 44.1 grams/mole. Using this value, the number of moles propane to be burned can be determined from the mass of propane given. Afterwards, this number of moles is multiplied by the heat of combustion to give the total heat produced from the reaction of the given mass of propane.

 14.50 kg propane  x <u> 1000 g </u> x <u>  1 mole propane   </u>  x <u>  2220 kJ  </u>   
                                     1 kg              44.1 g                     1 mole

= 729,931.97 kJ
8 0
3 years ago
Arrange the procedural steps, from start to finish, that are required to prepare indigo from nitrobenzaldehyde and acetone in ba
lions [1.4K]

Acetone has α-hydrogens (on both sides) and thus can be deprotonated to give a nucleophilic enolate anion. The aldehyde carbonyl is much more electrophilic than that of a ketone, and therefore reacts rapidly with the enolate.

<h3>What is nitrobenzaldehyde?</h3>
  • Synthesis. The synthesis of 3-nitrobenzaldehyde is achieved via nitration of benzaldehyde, which yields especially the meta-isomer. Creation allocation is about 19% for the ortho-, 72% for the meta- and 9% for the para isomers.
  • Acetone, propanone, or dimethyl ketone, is an organic combination with the formula (CH3)2CO. It is the easiest and smallest ketone. It is a colorless, highly volatile, and combustible liquid with a characteristic aromatic odor.
  • Nitration of benzene with conc nitric acid and conc sulphuric acid gives nitrobenzene. Chlorination with chlorine in the existence of anhydrous aluminum chloride gives meta nitro chlorobenzene.

To learn more about sulphuric acid, refer to:

brainly.com/question/4018599

#SPJ4

5 0
2 years ago
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