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3 years ago

What are the properties of the alkali earth metals

Chemistry

1 answer:

drek231 [11]3 years ago

5 0

Answer:

the alkaline earths possess many of the characteristics properties of metals.Alkaline earths have low electron affinities and low electronegativities. As with the alkali metals, the properties depend on the ease with which electrons are lost. The alkaline earths have two electrons in the outer shell. They have smaller atomic radii than the alkali metals. The two valence electrons are not tightly bound to the nucleus, so the alkaline earths readily lose the electron to form divalent cations.

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Select the atoms or ions drawn with valid Lewis dot structures. A) A carbon has a dot on top, right, bottom and to the left.a ni

charle [14.2K]

Answer:

B, C

Explanation:

The atoms or ions with the valid Lewis dot structures are B and C.

In A;

The Lewis structure of the carbon is correct. Each of the four dots represent the four valence electrons.

The nitrogen with one dot on top, left and to the bottom and has a charge of minus 3 is wrong. For it to have a charge of -3 it must have 8 lewis dots ( two on the top, right, bottom and to the left)

The nitrogen with four dots (on top, right, bottom and to the left) is wrong.

In B;

An oxygen has two dots on top and bottom and one dot to the left and to the right. This is correct , the 6 dots represent the valence electrons of oxygen.

In C;

A carbon has two dots on top, right, bottom and to the left and a charge of plus four. This is correct because the charge indicates that it has gained four extra electrons so its valence electrons is now 8.

In D;

An oxygen has two dots on top, left and to the bottom and a charge of minus 2. This is wrong because the lewis dots are incomplete. Two dots are missing.

6 0

3 years ago

3. Which one of the following materials would best allow infrared waves to pass through it?

vredina [299]

Tin foil I think Noh sure

6 0

3 years ago

Read 2 more answers

When 42.5 g of benzamide (C7H7NO) are dissolved in 500 g of a certain mystery liquid X, the freezing point of the solution is 6.

LuckyWell [14K]

Answer:

21.3g of Fe(NO₃)₃ are required to produce the same depression in freezing point of solution.

Explanation:

Freezing point depression is a colligative property which indicates, in determined mixture, the freezing point of solution is lower that the freezing point of the solvent, according the amount of solute.

Formula is: ΔT = Kf . m . i

Kf is the cryoscopic constant, which is particular for each solvent. We do not have that data, so we need to find it out in order to solve the question:

ΔT = Freezing point of pure solvent - Freezing point of solution.

This data is known → 6.40°C

m, means molality, moles of solute in 1kg of solvent. Let's get the moles of benzamide: 42.5 g . 1mol / 121g = 0.351 moles

m = 0.351 mol / 0.5kg = 0.702 m

As benzamide is an organic compound i, = 1. i are the number of ions dissolved in solution. Let's find out Kf:

6.40°C = Kf . 0.702 m . 1

6.40°C /0.702m = 9.11 °C/m.

Let's go to the next question.

ΔT is the same → 6.40°C

But this is, an inorganic salt, a ionic salt: Fe(NO₃)₃ → 1Fe³⁺ + 3NO₃⁻

For this case, we have 1 mol of Iron(III) and 3 nitrates, so i = 4

Let's replace data: 6.40°C = 9.11 °C/m . m . 4

6.40°C / (9.11 m/°C . 4) = 0.176 m

This data represents that, in 1 kg of solvent we have 0.176 moles of nitrate.

Mass of solvent X required in this case is 0.500 kg, so, the moles that are contained are: 0.500 kg . 0.176 mol/kg = 0.088 mol

Let's determine the mass of salt: 0.088 mol . 241.85g /1mol = 21.3 g

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3 years ago

Which describes the molecule shown below?

lana [24]

Answer:

Option D. Saturated alkane

Explanation:

To know which option is correct, it is important that we know what saturated and unsaturated compounds are in this context.

Saturated hydrocarbons are compounds which has only carbon to carbon single bonds (C–C) in its chain. A very good example of such compound is the Alkanes.

Unsaturated hydrocarbons are compounds which has either a carbon to carbon double bond (C=C) or a carbon to carbon triple bond (C≡C) in its chain. Examples of such compounds include alkenes and alkynes.

Now, let us answer the question given above bearing the meaning of saturated and unsaturated compounds in mind.

The compound given above contains only carbon to carbon (C–C) single bond.

Therefore, the compound is a saturated alkane.

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3 years ago

Complete the symbol equation for the preparation of sodium sulfate

Zielflug [23.3K]

2NaOH(aq) + H2SO4(aq) => Na2SO4(s) + 2H2O(l)

This is a neutralization reaction.

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3 years ago