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stiks02 [169]
3 years ago
7

Help pls i give 20 points

Chemistry
1 answer:
Sveta_85 [38]3 years ago
6 0
1. Physical- it is just changing states it’s still gold.
2. Chemical - oxidation is occurring which is a chemical change
3.chemical- when metal rusts it changes into iron oxide which is different than regular iron.

I’m not sure about the other 3. Sorry :( but I hope this kind of helps
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Explanation:

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3 years ago
Can the nature of a reactant be altered to speed up reaction
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Answer:

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6 0
3 years ago
PLEASE I NEED HELP ASAP!!!!
miv72 [106K]

The percent yield of the calcium hydroxide is 84.5%.

<h3>What is stoichiometry?</h3>

Stoichiometry enables us to obtain the mass of a substance form the equation of the reaction.

The equation of the reaction is;

CaCO3 + 2HCl -----> CaCl2 + CO2 + H2O

Number of moles of X = 40.0 grams/100 g/mol = 0.4 moles

Number of moles of HCl = 850/1000 * 1 M = 0.85 moles

If 1 mole of CaCO3 reacts with 2 moles of HCl

0.4 moles of  CaCO3 reacts with  0.4 moles  * 2 moles/1 mole

= 0.8 moles of HCl

Hence X is the limiting reactant.

The reaction is 1:1 then the amount of CO2  produced is 0.4 moles

Mass of CO2 = 0.4 CO2 * 44 g/mol = 17.6 g

2) The reaction equation is; 2NaOH + CaCO3 --->  Ca(OH)2 + Na2CO3

Number of moles of X = 25.0 grams/100 g/mol =  0.25 moles

Number of moles of NaOH= 40/1000 L * 2 M = 0.08 moles

If 1 mole of X reacts with 2 moles of NaOH

0.25 moles  reacts with   0.25 moles   * 2 moles /1 mole

= 0.5 moles

NaOH is the limiting reactant

2 moles of NaOH produces 1 mole of CO2

0.08 moles of NaOH produces 0.08 moles * 1 mole/2 moles

= 0.04 moles of CO2

Theoretical yield of CO2 =  0.04 moles of CO2 * 74 g/mol = 2.96  g

Percent yield = 2.5 g/ 2.96  g * 100

= 84.5%

Learn ore about percent yield:brainly.com/question/17042787

#SPJ1

5 0
2 years ago
Scientists can tell recycling reduces atmospheric emissions by knowing which of the following? o it takes more Btu to manufactur
Dmitriy789 [7]

Answer:

According to the Environmental Paper Network's Paper Calculator, it takes about 32 million BTUs of energy to produce 1 ton of virgin paper fiber. To produce 1 ton of recycled paper, it takes about 22 million BTUs.

so the answer could be it takes less Btu to manufacture recycled products than new ones

7 0
3 years ago
GIVING BRAINLIEST!!! A student observes a beaker of room temperature water resting on a table. She states that the beaker of wat
defon

Answer:

a

Explanation:

im thinking because the water is a room temperature there shouldnt be anm immence amount og heat energy for it to have a good amount of energy tho i could be wrong because its not moving it could have no energy.

8 0
3 years ago
Read 2 more answers
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