Which compound should require the highest temperature to melt? LiF, NaF, LiCl, NaCl

When using a calorimeter, the initial temperature of a metal is 70.4C. The initial temperature of the water is 23.6C. At the end

Sunny_sXe [5.5K]

1) 29.8 C

At the beginning, the metal is at higher temperature (70.4 C) while the water is at lower temperature (23.6 C). When they are put in contact, the metal transfers heat to the water, until they reach thermal equilibrium: at thermal equilibrium the two objects (the metal and the water have same temperature). Therefore, since the temperature of the water at thermal equilibrium is 29.8 C, the final temperature of the metal must be the same (29.8 C).

2) 6.2 C

The temperature change of the water is given by the difference between its final temperature and its initial temperature:

$\Delta T = T_f - T_i$

where

$T_f = 29.8 C\\T_i = 23.6 C$

Substituting into the formula,

$\Delta T=29.8 C-23.6 C=6.2 C$

And the positive sign means that the temperature of the water has increased.

3) -40.6 C

The temperature change of the metal is given by the difference between its final temperature and its initial temperature:

$\Delta T = T_f - T_i$

where

$T_f = 29.8 C\\T_i = 70.4 C$

Substituting into the formula,

$\Delta T=29.8 C-70.4 C=-40.6 C$

And the negative sign means the temperature of the metal has decreased.

5 0

3 years ago

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Learning Task 1: Determine what kind of carbon allotropes are the given pictures

kotegsom [21]

Answer:

1.C70

2.Fullerene

3.Lonsdaleite

4.Graphite

5.Diamond

6.Amorphous carbon

I hope this helps. thank you

Explanation:

4 0

3 years ago

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A trick shot archer shoots an arrow with a velocity of 30.0 m/s at an angle of 20.0 degrees with respect to the horizontal. An a

svlad2 [7]

Answer:

$u'=10.259\ m.s^{-1}$ is the initial velocity of tossing the apple.

the apple should be tossed after $\Delta t=0.0173\ s$

Explanation:

Given:

velocity of arrow in projectile, $v=30\ m.s^{-1}$

angle of projectile from the horizontal, $\theta=20^{\circ}$

distance of the point of tossing up of an apple, $d=30\ m$

Now the horizontal component of velocity:

$v_x=v\ cos\ \theta$

$v_x=30\times cos\ 20^{\circ}$

$v_x=28.191\ m.s^{-1}$

The vertical component of the velocity:

$v_y=v.sin\ \theta$

$v_y=30\times sin\ 20^{\circ}$

$v_y=10.261\ m.s^{-1}$

Time taken by the projectile to travel the distance of 30 m:

$t=\frac{d}{v_x}$

$t=\frac{30}{28.191}$

$t=1.0642\ s$

Vertical position of the projectile at this time:

$h=v_y.t-\frac{1}{2}g.t^2$

$h=10.261\times 1.0642-\frac{1}{2} \times 9.8\times 1.0642^2$

$h=5.3701\ m$

Now this height should be the maximum height of the tossed apple where its velocity becomes zero.

$v'^2=u'^2-2g.h$

$0^2=u'^2-2\times 9.8\times 5.3701$

$u'=10.259\ m.s^{-1}$ is the initial velocity of tossing the apple.

Time taken to reach this height:

$v'=u'-g.t'$

$0=10.259-9.8\times t'$

$t'=1.0469\ s$

We observe that $t>t'$ hence the time after the launch of the projectile after which the apple should be tossed is:

$\Delta t=t-t'$

$\Delta t=1.0642-1.0469$

$\Delta t=0.0173\ s$

8 0

3 years ago

Which bond(s) shown are double bonds?

Nikitich [7]

Answer:

I'm pretty sure its the 2nd one.

3 0

3 years ago

How is a light element like helium is formed in stars and how is a heavier element like gold formed by stars?

aliina [53]

Answer:

C

Explanation:

Because *censored*. Then the element *censored* your answer

7 0

3 years ago