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iogann1982 [59]
3 years ago
10

Which of the following is used in pencils?

Chemistry
2 answers:
goldenfox [79]3 years ago
8 0

Answer:

the first is graphite........

Mamont248 [21]3 years ago
3 0

Answer:

1st answer:  A. Graphite

2nd answer:  B.  Mercury

Explanation:

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Write the overall, balanced molecular equation and indicate which element is oxidized and which is reduced for the following rea
galina1969 [7]

Answer:

Cd(s) + AgNO₃(aq)  → Cd(NO₃)₂ (aq) + Ag(s)

Oxidized: Cd

Reduced: Ag

Explanation:

Cd(s) + AgNO₃(aq)  → Cd(NO₃)₂ (aq) + Ag(s)

Cd → Cd²⁺  +  2e⁻      Half reaction oxidation

1e⁻ + Ag⁺ → Ag           Half reaction reduction

Ag changed oxidation number from +1 to 0

Cd changed oxidation number from 0 to +2

Let's ballance the electrons

( Cd → Cd²⁺  +  2e⁻ ) .1

( 1e⁻ + Ag⁺ → Ag ) .2

Cd + 2e⁻ + 2Ag⁺  → 2Ag +  Cd²⁺  +  2e⁻

Finally the ballance equation is:

Cd(s) + 2AgNO₃(aq)  → Cd(NO₃)₂ (aq) + 2Ag(s)

4 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
Which of the following will occur soon after a population of prey increases slightly in size?
Lady bird [3.3K]
Your answer is D predator population will increase greatly. That's because if there's more prey there will be more food and its good for the predators to produce more because they don't got to worry about food. Speaking how they preys population grew.

So your answer is D.
4 0
3 years ago
How many grams of NH4ClO4 would dissolve in 250 mL at 30 C
baherus [9]
Ammonium perchlorate appears as a white, crystalline solid or powder. Classified as a division 1.1 explosive if powdered into particles smaller than 15 microns in diameter or if powdered into larger particles but thoroughly dried. Does not readily burn, but will burn if contaminated by combustible material. May explode under prolonged exposure to heat or fire. Used to make rocket propellants, explosives, pyrotechnics, as an etching and engraving agent, and in analytical chemistry.
8 0
3 years ago
For each of the following redox reactions in the, identify the oxidizing agent and the reducing agent.
NARA [144]
Anywhere between 5sogt2 and 776sogt2
5 0
3 years ago
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