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Kruka [31]
2 years ago
9

Chemical reactions occur when molecules or atoms collide so that the bonds between atoms break and new bonds form. breaking the

bonds of the reactants requires energy; whereas, bond formation releases energy. select the statements regarding energy changes during a reaction that are true.
Chemistry
1 answer:
katen-ka-za [31]2 years ago
8 0
If two substances react and the temperature of the mixture decreases, the reaction is endothermic<span>. If two substances react and the temperature of the mixture increases, the reaction is </span>exothermic<span>. A chemical reaction involves the </span>breaking<span> of bonds in the reactants and the forming of bonds in the products.</span>
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2ch4(g) c2h2(g) 3h2(g) describe what is happening within the system when it is at equilibrium in terms of concentrations, reacti
SashulF [63]

Balanced chemical reaction: 2CH₄(g) ⇄ C₂H₂(g) + 3H₂(g).

1) In a chemical reaction, chemical equilibrium is the state in which both reactants (methane CH₄) and products (ethyne C₂H₂ and hydrogen H₂) are present in concentrations which have no further tendency to change with time.  

2) At equilibrium, both the forward and reverse reactions are still occurring.

3) Reaction rates of the forward and backward reactions are equal and  there are no changes in the concentrations of the reactants and products.

4 0
3 years ago
Read 2 more answers
How many milliliters of a 3.4 M NaCl solution would be needed to prepare each solution?
Ksenya-84 [330]

Answer:

a. Approximately 1.3\; \rm mL.

b. Approximately 7.2\; \rm mL.

Explanation:

The unit of concentration "\rm M" is equivalent to "\rm mol \cdot L^{-1}", which means "moles per liter."

However, the volume of both solutions were given in mililiters \rm mL. Convert these volumes to liters:

\displaystyle 45\; \rm mL = 45\; \rm mL \times \frac{1\; \rm L}{1000\; \rm mL} = 0.045\; \rm L.

\displaystyle 330\; \rm mL = 330\; \rm mL \times \frac{1\; \rm L}{1000\; \rm mL} = 0.330\; \rm L.

In a solution of volume V where the concentration of a solute is c, there would be c \cdot V (moles of) formula units of this solute.

Calculate the number of moles of \rm NaCl formula units in each of the two solutions:

Solution in a.:

n = c \cdot V = 0.045\; \rm L \times 0.10\; \rm mol \cdot L^{-1} = 0.0045\; \rm mol.

Solution in b.:

n = c \cdot V = 0.330\; \rm L \times 0.074\; \rm mol \cdot L^{-1} = 0.02442\; \rm mol.

What volume of that 3.4\; \rm M (same as 3.4 \; \rm mol \cdot L^{-1}) \rm NaCl solution would contain that many

For the solution in a.:

\displaystyle V = \frac{n}{c} = \frac{0.0045\; \rm mol}{3.4\; \rm mol \cdot L^{-1}} \approx 0.0013\; \rm L.

Convert the unit of that volume to milliliters:

\displaystyle 0.0013\; \rm L = 0.0013\; \rm L \times \frac{1000\; \rm mL}{1\; \rm L} = 1.3\; \rm mL.

Similarly, for the solution in b.:

\displaystyle V = \frac{n}{c} = \frac{0.02442\; \rm mol}{3.4\; \rm mol \cdot L^{-1}} \approx 0.0072\; \rm L.

Convert the unit of that volume to milliliters:

\displaystyle 0.0072\; \rm L = 0.0072\; \rm L \times \frac{1000\; \rm mL}{1\; \rm L} = 7.2\; \rm mL.

8 0
3 years ago
If a question cannot be tested and observed, it cannot be answered with science. (2 points) True or False?
boyakko [2]

Answer:

True

Explanation:

If a question cannot be tested and observed, it cannot simply be answered by science.

Science works with observable and testable ideas and not on metaphysics.

  • Science presents a methodical approach into investigating phenomenon and answering likely questions in a logical manner.
  • The body of facts and data gathered through observations and tests are used to ramify the conclusion of a scientific study.
  • Without such, it is impossible to do the work of science.
3 0
3 years ago
Mary starts from her house, walks 80 meters south, and stops to chat with her aunt on the sidewalk. After chatting for a few min
Olenka [21]
(80+125+45) / 10 = 250/10 =25
25 meters per minute= 0.41 meters/second

the direction and stopping time is irrelevant to the problem.
6 0
3 years ago
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AleksandrR [38]

Answer:

k(+)

NH4(+)

Al3(+)

Explanation:

cations are those elements who donate their electrons and we put a positive charge on it and receivers get negative charge and they are called anion.....Thank you so,much Please let me know how you feel and is helps you or not....

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