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VashaNatasha [74]
4 years ago
6

Which of the following is not an indication of a chemical reaction?

Chemistry
1 answer:
eimsori [14]4 years ago
7 0

Answer: Option (3) is the correct answer.

Explanation:

A reaction due to which there occurs change in chemical composition of reactants is known as a chemical reaction.

For example, evolution of heat when two substances combine together shows a chemical reaction has taken place between the substances.

Whereas a reaction which does not bring any changes in chemical composition of the reactants is known as a physical reaction.

For example, boiling point, melting point, mass, volume etc are all physical properties.

Thus, we can conclude that out of the given options a substance melts when sitting in the Sun, is not an indication of a chemical reaction.

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Consider the reaction: CH4 + 2O2 = CO2 + 2H2O
crimeas [40]

Answer:

The answer to your question is:

a)  80 g of O2

b) O2, 15.13 g of CO2

c) It's not posible to know which is the limiting reactant.

Explanation:

Reaction                             CH4   +   2O2   ⇒   CO2   +   2H2O

a. Calculate the grams of O2 needed to react with 20.00 grams of CH4. _____________

MW CH4 = 16 g

MW O2 = 32 g

                               16 g of CH4 ----------------  2(32) g of O2

                               20 g              --------------    x

                               x = (20 x 64) / 16 = 80 g of O2

b. Given 15.00 g. of CH4 and 22.00 g. of O2, identify the limiting reactant and calculate the grams of CO2 that can be produced. LR _________ grams CO2 _________ .  

                                CH4   +   2O2   ⇒   CO2   +   2H2O

                                15 g         22 g

                                16 g of CH4 ----------------  64 g of O2

                                15 g of CH4  ---------------   x

                               x = (15 x 64) / 16 = 60 g of O2

The Limiting reactant is O2 because it is necessary 60g of O2 for 16 g of CH4 and there are only 22.

                                 CH4   +   2O2   ⇒   CO2   +   2H2O

                        64 g of O2 ------------------  44 g of CO2

                        22 g of O2 ------------------   x

                        x = (22 x 44)/ 64 = 15. 13 g of CO2

c. For the reaction CH4 + 2O2 = CO2 + 2H2O, if you have 10.31 g. of CH4 and an unknown amount of oxygen, and form 20.00 g. of CO2, i. Identify if there is a limiting reactant ______________ ii. Calculate the number of grams of the limiting reactant present if there is one. ______________  

                           CH4   +   2O2   ⇒   CO2   +   2H2O                              

                           10.31 g                     20 g

We can identify the limiting reactant if we know the quantity of the reactants, if we only know the quantity of one it is not posible to which is the limiting reactant.

4 0
3 years ago
A bobsled has a momentum of 4000 0 kg* m/s to the south. Friction on the track reduces its momentum to 500 kg* m/s to the south.
faltersainse [42]
The correct answer is c
6 0
3 years ago
Read 2 more answers
Calculate the percentage by mass of the indicated element in the following compounds. Hydrogen in ascorbic acid, HC6H7O6, also k
Scorpion4ik [409]

Answer: The mass percent of hydrogen in ascorbic acid is 4.5 %

Explanation:

In C_6H_8O_6, there are 6 carbon atoms, 8 hydrogen atoms and 6 oxygen atoms.

To calculate the mass percent of element in a given compound, we use the formula:

\text{Mass percent of hydrogen}=\frac{\text{Mass of hydrogen}}{\text{Molar mass of ascorbic acid}}\times 100

Mass of hydrogen = 8\times 1g/mol=8g

Molar Mass of ascorbic acid =6\times 12g/mol+8\times 1g/mol+6\times 16g/mol=176g

Putting values in above equation, we get:

\text{Mass percent of hydrogen}=\frac{8g}{176}\times 100=4.5\%

Hence, the mass percent of of hydrogen in ascorbic acid is 4.5 %.

8 0
3 years ago
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uysha [10]
The answer is double displacement is the answer
3 0
3 years ago
Which of these humans activities is a serious threat to marine ecosystems
Paraphin [41]

Answer:

Pollution, non native species being introduced, and other human activities

Explanation:

Human activities affect marine ecosystems as a result of pollution, overfishing, the introduction of invasive species,and acidification, which all impact on the marine food web and may lead to largely unknown consequences for the biodiversity and survival of marine life forms.

5 0
3 years ago
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