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3 years ago

What does the law of conservation of energy state about energy in a closed system

Physics

1 answer:

Naya [18.7K]3 years ago

5 0

Answer:

The total energy in a closed system (a system that isolated from its surroundings) is always constant.

Explanation:

The law of conservation energy states that:

The total energy in a closed system (a system that isolated from its surroundings) is always constant.

What this law means is that energy can never be created or destroyed but can only be converted from one form to another form or example the conversion of energy from potential energy to kinetic energy which is seen by a falling object from a height.

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Glycerin (C3H8O3) is a nonvolatile liquid. What is the vapor pressure of a solution made by adding 154 g of glycerin to 316 mL o

garri49 [273]

Answer:

$P_{sol}=50.4\ mm.Hg$

Explanation:

According to given:

molecular mass of glycerin, $M_g=3\times 12+8+3\times 16=92\ g.mol^{-1}$

molecular mass of water, $M_w=2+16=18\ g.mol^{-1}$

∵Density of water is $0.992\ g.cm^{-3}= 0.992\ g.mL^{-1}$

∴mass of water in 316 mL, $m_w=316\times 0.992=313.5 g$

mass of glycerin, $m_g=154\ g$

pressure of mixture, $P_x=55.32\ torr= 55.32\ mm.Hg$

temperature of mixture, $T_x=40^{\circ}C$

Upon the formation of solution the vapour pressure will be reduced since we have one component of solution as non-volatile.

moles of water in the given quantity:

$n_w=\frac{m_w}{M_w}$

$n_w=\frac{313.5}{18}$

$n_w=17.42 moles$

moles of glycerin in the given quantity:

$n_g=\frac{m_g}{M_g}$

$n_g=\frac{154}{92}$

$n_g=1.674 moles$

Now the mole fraction of water:

$X_w=\frac{n_w}{n_w+n_g}$

$X_w=\frac{17.42}{17.42+1.674}$

$X_w=0.912$

Since glycerin is non-volatile in nature so the vapor pressure of the resulting solution will be due to water only.

$\therefore P_{sol}=X_w\times P_x$

$\therefore P_{sol}=0.912\times 55.32$

$P_{sol}=50.4\ mm.Hg$

7 0

3 years ago

A child uses a rubber band to launch a bottle cap at an angle of 37.0° above the horizontal. The cap travels a horizontal distan

zavuch27 [327]

Answer:

Initial velocity will be 1.356 m/sec

Explanation:

Let the initial speed = u

Angle at which rubber band is launched = 37°

Horizontal component of initial velocity $u_x=ucos\Theta =ucos37^{\circ}=0.7986u$

Time is given as t = 1.20 sec

Distance in horizontal direction = 1.30 m

We know that distance = speed × time

So time $t=\frac{distance}{speed}$

$1.20=\frac{1.3}{0.7986u}$

$u=1.356m/sec$

So initial velocity will be 1.356 m/sec

3 0

3 years ago

When all else remains the same, what effect would decreasing the focal length have on a convex lens?

aniked [119]

<h3>Answer;</h3>

It would make the lens stronger.

<h3>Explanation;</h3>

The focal length is the distance between the optical center or the center of the lens to the focal point of a convex or concave lens.
The power of the convex lens is lens ability to undertake refraction or bend light. It is given as the reciprocal of focal length.
Power of the lens = 1/ f; therefore the smaller the focal length the higher the power and the larger the focal length the lower the power.
Thus; decreasing the focal length of a convex lens makes the lens stronger.

4 0

3 years ago

Read 2 more answers

How much electrical energy is used by a 75 W laptop that is operating for 12 minutes?

Liono4ka [1.6K]

"1 watt" means 1 joule of energy per second.

75 W means 75 joules/sec .

Energy = (75 Joule/sec) x (12 min) x (60 sec/min)

Energy = (75 x 12 x 60) (Joule-min-sec / sec-min)

Energy = 54,000 Joules

7 0

2 years ago

Can someone please help me

Tamiku [17]

F = 153 N

$\theta = 11.3°$

Explanation:

Let us define first our directional convention. Anything pointing up or to the right is considered positive and anything pointing down or to the left is considered negative. Now let's look at the components $F_{x}$ and $F_{y}$ :