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3 years ago

Why do you think elements must be heated before they emit colored light?

1 answer:

4 0

The colored light emitted is energy and in order to emit energy the element should first obtain energy. The energy absorbed by the substance can be in the form of radiation, heat or electricity. Hope this answers the question. Have a nice day.

You might be interested in

What did Rutherford's gold foil experiment tell about the atom?

VLD [36.1K]

The alpha particles that were fired at the gold foil were positively charged. ... These experiments led Rutherford to describe the atom as containing mostly empty space, with a very small, dense, positively charged nucleus at the center, which contained most of the mass of the atom, with the electrons orbiting the nucleus.

hope this helped

3 0

3 years ago

When dissolved in water, a neutral molecule of calcium chloride dissociates into three ions - one calcium ion and two chloride i

Mashcka [7]

Explanation:

Calcium chloride is an ionic compound as it is formed by transfer of an electron to each chlorine atom.

So, being an ionic compound calcium chloride is able to dissociate completely into water.

Hence, the dissociation reaction will be as follows.

$CaCl_{2}(s) \rightarrow Ca^{2+}(aq) + 2Cl^{-}(aq)$

Since, two electrons has been lost by single calcium atom. Therefore, calcium atom will have a charge of +2.

Thus, we can conclude that the charge on the calcium ion, in elementary units is +2.

8 0

3 years ago

A 151.5-g sample of a metal at 75.0°C is added to 151.5 g at 15.1°C. The temperature of the water rises to 18.7°C. Calculate the

Kryger [21]

Answer:

The specific heat capacity of the metal is 0.268 J/g°C

Explanation:

Step 1: Data given

Mass of the metal = 151.5 grams

The temperature of the metal = 75.0 °C

Temperature of water = 15.1 °C

The temperature of the water rises to 18.7°C.

The specific heat capacity of water is 4.18 J/°C*g

Step 2: Calculate the specific heat capacity of the metal

heat lost = heat gained

Q = m*c*ΔT

Qmetal = - Qwater

m(metal) * c(metal) * ΔT(metal) = m(water) * c(water) * ΔT(water)

⇒ mass of the metal = 151.5 grams

⇒ c(metal) = TO BE DETERMINED

⇒ΔT( metal) = T2 - T1 = 18.7 °C - 75.0 °C = -56.3 °C

⇒ mass of the water = 151.5 grams

⇒ c(water) = 4.184 J/g°C

⇒ ΔT(water) = 18.7° - 15.1 = 3.6 °C

151.5g * c(metal) * -56.3°C = 151.5g * 4.184 J/g°C * 3.6 °C

c(metal) = 0.268 J/g°C

The specific heat capacity of the metal is 0.268 J/g°C

5 0

4 years ago

If the formula for potassium chlorate is KClO3 and the formula for magnesium fluoride is MgF2, then what isthe formula for magne

mr_godi [17]

The formula for magnesium chlorate is Mg(ClO3)2.

5 0

3 years ago

Given any two elements within a group, is the element with the larger atomic number likely to have a larger or smaller atomic ra

zhenek [66]

Answer:

Atomic radius of sodium = 227 pm

Atomic radius of potassium = 280 pm

Explanation:

Atomic radii trend along group:

As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.

Consider the example of sodium and potassium.

Sodium is present above the potassium with in same group i.e, group one.

The atomic number of sodium is 11 and potassium 19.

So potassium will have larger atomic radius as compared to sodium.

Atomic radius of sodium = 227 pm

Atomic radius of potassium = 280 pm

3 0

3 years ago