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2 years ago

Is francium found in nature or lab?

Chemistry

1 answer:

ddd [48]2 years ago

8 0

Answer:

It was the last element first discovered in nature, rather than by synthesis. Outside the laboratory, francium is extremely rare, with trace amounts found in uranium and thorium ores, where the isotope francium-223 continually forms and decays

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Suppose that a dependent quantity increases when the independent quantity is decreased. This kind of proportional relationship b

Anna71 [15]

I thinks it’s not this article we should cajnges it

3 0

2 years ago

A piece of high-density Styrofoam measuring 24.0 cm by 36.0 cm by 5.0 cm floats when placed in a tub of water. When a 1.5 kg boo

zheka24 [161]

Explanation:

The given data is as follows.

Width of Styrofoam = 24.0 cm

Length of Styrofoam = 36.0 cm

Height of Styrofoam = 5.0 cm

Therefore, volume of the Styrofoam will be calculated as follows.

Volume = length × width × height

= (36.0 × 24.0 × 5.0) $cm^{3}$

= 4320 $cm^{3}$

or, = $4.32 \times 10^{3} cm^{3}$

As Styrofoam partially sinks at 3.0 cm and total height of Styrofoam is 5.0 cm. Hence, height of Styrofoam above the water is (5.0 - 3 cm) = 2 cm.

So, volume of water displaced is as follows.

24.0 cm × 36.0 cm × 2.0 cm

= $1.73 \times 10^{3} cm^{3}$

Hence, mass of displaced water is as follows.

mass = density × volume

= $1.00 g/cm^{3} \times 1.73 \times 10^{3} cm^{3}$

= $1.73 \times 10^{3} g$

Since, book is placed on the Styrofoam. Therefore, mass of water displaced is also equal to the following.

Mass of water displaced = mass of book + mass of Styrofoam

$1.73 \times 10^{3} g$ = 1500 g + mass of Styrofoam

(1730 - 1500) g = mass of Styrofoam

mass of Styrofoam = 230 g

Therefore, calculate the density of Styrofoam as follows.

Density = $\frac{mass}{volume}$

= $\frac{230}{4.32 \times 10^{3} cm^{3}}$

= $53.24 \times 10^{-3} g cm^{-3}$

Thus, we can conclude that the density of Styrofoam is $53.24 \times 10^{-3} g cm^{-3}$ .

4 0

2 years ago

A molecule has three bonded atoms around the central atom. The central atom does not have any lone pairs. What is the geometry o

adelina 88 [10]

Answer:

trigonal planar

Explanation:

Tri=three, three-dimensional arrangement of the atoms that constitute a molecule.

5 0

2 years ago

Match the separation techniques with the correct descriptions.

nordsb [41]

Answer:

Explanation:

1 = A

Sublimation is the process where by a sample is heated to pass through solid phase to gaseous phase without the intermittent liquid phase. Example of substance that sublime is camphor.

2 = D

Decantantion

5 = F

Filtration is the process a liquid from solid using a porous material. This technique requires a set up and a good porous material eg filter paper.

6 = B

This technique is to separate a mixture of solids by converting them from solid phase to gaseous phase since they sublime.

3 = deposition.

The answer isn't in the option but deposition is the process of substance in gaseous phase to change into solid state without passing through liquid phase. Deposition is the opposite of sublimation.

4 = E

4 0

3 years ago

Frank pulls down on a garage door with a force of 80 N. If the door weighs 210 N, what is the net downward force on the door?

elena-s [515]

Answer:

290 N

Explanation:

Total downward force = Force applied on the door in bringing it down + weight of the door

Total downward force = 80 + 210

Total downward force = 290N

7 0

3 years ago

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