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3 years ago

FREE BRAINLIEST IF CORRECT

Chemistry

2 answers:

Veronika [31]3 years ago

8 0

Answer:

Reflection.

Explanation:

An echo is an example of wave reflection. Reflection occurs when waves bounce back from a surface they cannot pass through.

Hope this helps

tangare [24]3 years ago

6 0

Answer:

reflection because they reflect back for the animals to know what is happening

Explanation:

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In general, both cations and anions will __________ as you go down a group.

madam [21]

A because cation is positive and anion is negative evening it out at constant.

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2 years ago

Which process involves an increase in entropy? crystallization of a solute from a solution ice melting into liquid water iodine

GrogVix [38]

Ice melting into liquid water.

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3 years ago

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What is the hydronium ion concentration of a 0.100 M acetic acid solution with Ka = 1.8 × 10-5? The equation for the dissociatio

evablogger [386]

Answer:

1.3×10⁻³ M

Explanation:

Hello,

In this case, given the dissociation reaction of acetic acid:

$CH_3CO_2H(aq) + H_2O(l) \rightleftharpoons H_3O^+(aq) + CH_3CO_2^-(aq)$

We can write the law of mass action for it:

$Ka=\frac{[H_3O^+][CH_3CO_2^-]}{[CH_3CO_2H]}$

Of course, excluding the water as heterogeneous substances are not included. Then, in terms of the change $x$ due to the dissociation extent, we are able to rewrite it as shown below:

$1.8x10^{-5}=\frac{x*x}{0.100-x}$

Thus, via the quadratic equation or solve, we obtain the following solutions:

$x_1=-0.00135M\\x_2=0.00133M$

Obviously, the solution is 0.00133M which match with the hydronium concentration, thus, answer is: 1.3×10⁻³ M in scientific notation.

Regards.

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3 years ago

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What determines the amount of chemical energy a substance has?

Ratling [72]

Chemical energy is the kind of energy stored in the bonds formed by atoms and molecules in chemical compounds and elements. This energy is released during a chemical reaction and heat is often given out in the process. These kind of reactions where heat is given out as a by product are called exothermic reactions.

The major factor that determines how much chemical energy a substance has is the mass of that substance. Mass is defined as the amount of matter in a substance.

The higher the mass of a substance, the more concentrated that substance is and subsequently the greater the number of atoms and molecules.

Logically, the higher the number of atoms and molecules then the greater the number of bonds in that substance and subsequently the more the amount of chemical energy stored therein.

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2 years ago

What is the binding energy of a nucleus that has a mass defect of 5.81*10-^29 kg

IrinaVladis [17]

Answer:

Choice A: Approximately $5.23 \times 10^{-29}$ joules.

Explanation:

Apply the famous mass-energy equivalence equation to find the energy that correspond to the $\rm 5.81\times 10^{-29}$ kilograms of mass.

$E = m \cdot c^{2}$ ,

where

$E$ stands for energy,
$m$ stands for mass, and
$c$ is the speed of light in vacuum.

The speed of light in vacuum is a constant. However, finding the right units for this value can simplify the calculations a lot. What should be the unit of $c$ ?

The mass given is in the appropriate SI unit:

Mass is in kilograms.

Thus, proceed with the speed of light in SI units. The SI unit for speed is meters per second. For the speed of light, $c \approx \rm 3.00\times 10^{8}\;m\cdot s^{-1}$ .

Apply the mass-energy equivalence:

$\begin{aligned} E &= m \cdot c^{2} \\ &= \rm 5.81\times 10^{-29}\; kg \times {\left(3.00\times 10^{8}\; m\cdot s^{-1}\right)}^{2}\\ &\approx \rm 5.23\times 10^{-12}\;kg\cdot m^{2}\cdot s^{-2} \end{aligned}$ .

The unit of energy is not in joules. Don't be alerted. Consider the definition of a joule of energy. One joule is the work done on an object when a force of one newton acts on the object in the direction of the force through the distance of one meter. (English Wikipedia.)

$\rm 1\; J = 1\; N \times 1\; m$ .

However, a force of one newton is defined as the force required to accelerated an object with a mass of one kilogram (not gram) at a rate of one meter per second squared. (English Wikipedia.)

$\begin{aligned}\rm 1\; J &= \rm 1\; N \times 1\; m\\ & = \rm \left(1\; kg\times 1\; m\cdot s^{-2}\right)\times 1\; m\\ &= \rm 1\; kg \cdot m^{2}\cdot s^{-2}\end{aligned}$ .

In other words, the mass defect here is also $\rm 5.23\times 10^{-12}\; J$ .

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3 years ago

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