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3 years ago

The longest day, and shortest night, of the year occurs on the

Chemistry

1 answer:

BaLLatris [955]3 years ago

5 0

Answer:

This is the first answer,

winter solstice

The winter solstice occurs during the hemisphere's winter. In the Northern Hemisphere, this is the December solstice (usually December 21 or 22) and in the Southern Hemisphere, this is the June solstice (usually June 20 or 21).

and this is the second one,

the tilt of the Earth on its axis

Seasons change because of the tilt of the Earth and the planet's movement around the Sun. Did you know? It takes about 365.25 days for the Earth to orbit the Sun. We have leap years to make up for the extra ¼ day!

You might be interested in

What is the molarity of 0.50g of Na dissolved in a 1.5 L solution?

lara [203]

M = mols of solute / L of solution

Convert .50 g Na to mols Na by dividing by 22.99 and then dividing that by 1.5, which gives you a 0.014 M solution.

5 0

3 years ago

Which of the following is a reasonable ground-state electron configuration?A) 1s21p62d2B) 1s22s42p6C) 1s22s22p5D) 1s22s22d6

Semenov [28]

Answer:

Option C) 1s² 2s² 2p⁵

Explanation:

Ground-state is the configuration of the electrons when every electron of the atom occupies the lowest possible energy level.

The rank of energy of the orbitals may be remembered using Aufbau rules, and it is:

1s² < 2s² < 2p⁶ < 3s² < 3p⁶ < 4s² < 3d¹⁰ < 4p⁶ < 5s² < 4d¹⁰ < 5p⁶ < 6s² < 4f¹⁴ < 5d¹⁰ < 6p⁶ < 7s² < 5f¹⁴ < 6d¹⁰ < 7p⁶

Then, to find whether an electron configuration corresponds to a ground-state one, you must check that the previous order is preserved.

Option A). 1s² 1p⁶ 2d²

The orbital 1p does not exist. So this one is discarded.

Option B) 1s² 2s⁴ 2p⁶

The maximum number of electrons in an s orbital is 2, so 2s⁴ is impossible, and this option is discarded.

Option C) 1s² 2s² 2p⁵

This is correct because the orbitals are filled in the correct increasing energy order, without jumping any one.

Option D) 1s² 2s² 2d⁶

Orbital 2d does not exist, so this option is also discarded.

4 0

3 years ago

A piece of unknown metal with mass 68.6 g is heated to an initial temperature of 100 °C and dropped into 42 g of water (with an

kogti [31]

The piece of unknown metal is in thermal equilibrium with water such that Q of metal is equal to Q of the water. We write this equality as follows:

-Qm = Qw

Mass of metal (Cm)(ΔT) = Mass of water (Cw) (ΔT)

where C is the specific heat capacities of the materials.

We calculate as follows:

-(Mass of metal (Cm)(ΔT)) = Mass of water (Cw) (ΔT)

-68.6 (Cm)(52.1 - 100) = 42 (4.184) (52.1 - 20)

Cm = 1.717 -----> OPTION C

8 0

3 years ago

A 0.652-g sample of a pure strontium halide reacts with excess sulfuric acid. the solid strontium sulfate formed is separated, d

seraphim [82]

Answer:

The formula of the original halide is SrCl₂.

Explanation:

The balanced equation of this reaction is:

SrX₂ + H₂SO₄ → SrSO₄ + 2 HX, where X is the halide.

From the equation stichiometry, 1.0 mole of strontium halide will result in 1.0 mole of SrSO₄.

The number of moles of SrSO₄ (n = mass/molar mass) = (0.755 g) / (183.68 g/mole) = 4.11 x 10⁻³ mole.

The number of moles of SrX are 4.11 x 10⁻³ moles from the stichiometry of the balanced equation.

n = mass / molar mass, n = 4.11 x 10⁻³ moles and mass = 0.652 g.

The molar mass of SrX₂ = mass / n = (0.652) / (4.11 x 10⁻³ moles) = 158.62 g/mole.

The molar mass of SrX₂ (158.62 g/mole) = Atomic mass of Sr (87.62 g/mole) + (2 x Atomic mass of halide X).

The atomic mass of halide X = (158.62 g/mole) - (87.62 g/mole) / 2 = 71 / 2 g/mole = 35.5 g/mole.

This is the atomic mass of Cl.

So, the formula of the original halide is SrCl₂.

4 0

3 years ago

What happens to the molecules of water as it freezes?

Nataly [62]

When Water freezes or begin to freeze, it molecules start to slow down enough that their attraction arrange into one shape till they melt again.

6 0

3 years ago