There are several differences between a physical and chemical change in matter or substances. A physical change in a substance doesn't change what the substance is. In a chemical change where there is a chemical reaction, a new substance is formed and energy is either given off or absorbed.

3 0

3 years ago

Rhodium-101 has a half life of 3.3 years. What percent of the sample will remain after 6.6 years?

babunello [35]

Answer:

25%

Explanation:

Half life means that 50% of the sample is gone at 3.3 years. This means that an additional 3.3 years (total 6.6 years) will reduce the sample a further 50% from the point at 3.3 years. In numbers, this means 50% of 50% (0.50*0.50), which is 25%.

5 0

3 years ago

Suppose a mercury thermometer contains 3.250g of mercury and has a capillary that is 0.180mm in diameter.. How far does the merc

Helga [31]

1) You need to get volume of both temperatures by using first attached formula V= Mass/Density $V_1 = (3.250 g)/(13.596 g/(cm^3)) = .2390 cm^3
At 25 degrees C (V_2e have:

V_2 = (3.250 g)/(13.534 g/(cm^3)) = .2401 cm^3$

2) Using the second formula you get the height of 0 degree
$h = V/(pi * r^2)


h_1 =(.2390 cm^3)/(pi*(.009 cm)^2) = 939.2 cm$

(radius in cm is $(0.180 mm) / 2 * (1 cm)/(10 mm) or .009 cm$

3) Then with h1 you can easily get the height of 25 degrees
$h_2 =(.2401 cm^3)/(pi*(.009 cm)^2) = 943.5 cm$

Subtract 943.5 cm - 939.2 cm, and obtain a rise in mercury height of 4.3 cm

5 0

3 years ago

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In the modern periodic table when elements are arranged according to their atomic

9966 [12]

In the modern periodic table when elements are arranged according to their atomic number.

3 0

3 years ago