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3 years ago

What happens to the density when water is poured into a empty glass?

1 answer:

3 0

-- The density of the glass alone doesn't change.

-- The density of the water alone doesn't change.

-- The density of (the entire glass + everything IN IT) increases,
because the part that used to be air (with very low density) is
changed to water (with much higher density than the air had).

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A 190 g rock at 20°C is completely immersed in 600 g of water at 80°C. Which one of the following statements is true right after

Umnica [9.8K]

Rock is completely immersed in hot water. By the second law of thermodynamics, thermal energy or heat is transferred from substance with higher temperature to substance with lower temperature until they come to thermal equilibrium i.e. both at same temperature.

It is given here that rock is at 20°C which is at lower temperature than water at 80°C. ∴Heat or thermal energy flows from water to rock. So, right choice is-

A. The water gives the rock thermal energy and gets no thermal energy in return.

8 0

3 years ago

A mercury thermometer is constructed as

Tamiku [17]

Answer:

The change in height of the mercury is approximately 2.981 cm

Explanation:

Recall that the formula for thermal expansion in volume is:

$\frac{\Delta V}{V_0} =\alpha_V\, \Delta\, T\\\Delta V = V_0\,\, \alpha_V\,\,\Delta C$

from which we solved for the change in volume $\Delta V$ due to a given change in temperature $\Delta T$

We can estimate the initial volume of the mercury in the spherical bulb of diameter 0.24 cm ( radius R = 0.12 cm) using the formula for the volume of a sphere:

$V_0=\frac{4}{3} \pi \, R^3\\V_0=\frac{4}{3} \pi \, (0.12\,cm)^3\\V_0=0.007238\,cm^3$

Therefore, the change in volume with a change in temperature of 36°C becomes:

$\Delta V = V_0\,\, \alpha_V\,\,\Delta C\\\Delta V = 0.007238229\, cm^3\,(0.000182)\,(36)\\\Delta V=0.0000474248\, cm^3$

Now, we can use this difference in volume, to estimate the height of the cylinder of mercury with diameter 0.0045 cm (radius r= 0.00225 cm):

$V_{cyl}=\pi r^2\,h\\h =\frac{V_{cyl}}{\pi r^2} \\h=\frac{0.0000474248\, cm^3}{\pi \, (0.00225\,cm)^2} \\h=2.98188 \,cm$

8 0

3 years ago

How long was a 50 W lightbulb left on for if 500,002 J were burned?

saveliy_v [14]

" 50 W " means " 50 Watts " or " 50 Joules per second ".

(500,002 J) / (50 J/sec) = <em>10,000.04 seconds</em>

(That's 2 hours 46 minutes 40.04 seconds.)

3 0

3 years ago

Use the periodic table from the lesson to answer the following question.

kodGreya [7K]

Answer:

18.99u or 19u

Explanation:

Mass number=No of protons+No of neutrons

$\\ \sf\longmapsto 9+10$

$\\ \sf\longmapsto 19u$

Fluorine has atomic number=9
The Electronic configuration is given by

$\\ \sf\longmapsto 1s^22s^22p^5$

7 0

3 years ago

Read 2 more answers

The pressure, P, of a gas varies directly with its temperature, T, and inversely with its volume, V, according to the equation f

lbvjy [14]

The equation formula:
P V = n R T
1,245 * 2 l = n R * 300 K
n R = 1,245 * 2 : 300 = 8.3
P * 2.5 l = n R * 400 K
P * 2.5 = 8.3 * 400
P = 3,320 : 2.5 = 1328 J
Answer: A ) 1,328 joules.

7 0

3 years ago

Read 2 more answers