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2 years ago

Two examples of chemical reactions that involved a thermal energy change:

Physics

1 answer:

zzz [600]2 years ago

6 0

Answer:

Option 1 is endothermic

Option 2 is exothermic

Explanation:

In Chemistry, Exothermic reactions are reactions whereby heat energy is transferred to the surroundings and the temperature of the surroundings increases. Endothermic reactions are those whereby heat energy from the surroundings is absorbed and thereby making the temperature of the surroundings to decrease.

This means in simple terms that endothermic reactions will have heat on the reaction side of the equation while exothermic will have heat on the product side of the equation.

Thus;

Option 1 is endothermic since it has heat absorbed on the reactant side.

Option 2 is exothermic since it gives off heat on the product side.

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Two identical charges q placed 2.0 mapart exert forces of magnitude 4.0 N on each other What is the value of the charge q? a) q

katen-ka-za [31]

Answer:

c) $4.2*10^{-5}C$

Explanation:

Coulomb's law says that the force exerted between two charges is inversely proportional to the square of distance between them, and is given by the expression:

$F=\frac{kq_{1}q_{2}}{r^{2}}$

where k is a proportionality constant with the value $k=9*10^{9}\frac{Nm^{2}}{C^{2}}$

In this case $q_{1}=q_{2}=q$ , so we have:

$F=\frac{kq^{2}}{r^{2}}$

Solving the equation for q, we have:

$kq^{2}=Fr^{2}$

$q^{2}=\frac{Fr^{2}}{k}$

$q=\sqrt{\frac{Fr^{2}}{k}}$

Replacing the given values:

$q=\sqrt{\frac{4.0N*(2.0m)^{2}}{9*10^{-9}\frac{Nm^{2}}{C^{2}}}}$

$q=4.2*10^{-5}C$

3 0

3 years ago

Some good estimates about the human body can be made if it is assumed that we are made mostly of water. The mass of a water mole

Bezzdna [24]

Answer:

Explanation:

Given

mass of water molecule $m=2.99\times 10^{-26}\ kg$

mass of person $M=62\ kg$

It is given that body is mostly made up of water

suppose n water molecules constitutes 62 kg

so $n\times m=M$

$n=\frac{62}{2.99\times 10^{-26}}$

$n=20.73\times 10^{26}\ kg$

6 0

3 years ago

Speed differs from velocity in the same way that __________ differs from displacement.

lyudmila [28]

Speed differs from velocity in the same way that distance differs from displacement.

5 0

3 years ago

Read 2 more answers

The Coulomb force between two charges q1 and q2 at separation r in the air is 10N. If half of the separation is filled with medi

adoni [48]

Answer:

The value of new coulomb force is 1.43 N.

Explanation:

Given;

Coulomb's force in vacuum (air), $F_v$ = 10 N

dielectric constant, K = 7

The Coulomb's force between two charges separated by a distance r in a vacuum is given as;

$F_v = \frac{1}{4\pi \epsilon_0} \frac{q_1q_2}{r^2}$

The Coulomb's force between two charges separated by a distance r in a medium with dielectric constant is given as

$F_m = \frac{1}{4\pi K\epsilon_0} \frac{q_1q_2}{r^2}$

Take the ratio of the two forces;

$\frac{F_v}{F_m} = \frac{1}{4\pi \epsilon_0} \frac{q_1q_2}{r^2} \ \times \ \frac{4\pi K\epsilon_0 r^2}{q_1q_2} = K\\\\\frac{F_v}{F_m} = K\\\\\frac{10}{F_m} = 7\\\\F_m = \frac{10}{7} \\\\F_m = 1.43 \ N$

Therefore, the value of new coulomb force is 1.43 N.

5 0

3 years ago

The molecular mass of sodium oxide (Na2O) is

tresset_1 [31]

<span>The answer is 62 u. The molecular mass of a molecule (Mr) is the sum of atomic masses (Ar) of its elements. Ar(Na) = 23 u. Ar(O) = 16 u. Therefore, the molecular mass of sodium oxide is 62 u: Mr(Na2O) = 2 * Ar(Na) + Ar(O) = 2 * 23 u + 16 u = 46 + 16 = 62 u.</span>

7 0

3 years ago