All elements can be classified as metals, metalloids, or ?

In the lab you measure a clean dry crucible and cover to be 24.36 grams. You obtain a 2cm piece of pure magnesium metal. After s

mart [117]

Answer:

1) 0.3g Mg

2)0.5g MgO

3)0.2g O

4)0.01mol Mg & 0.01mol O

5)0.01mol MgO

6) Empirical formula MgO

Explanation:

The mass og Mg is obtained by substracting 24.36g from 24.66g:

24.66 - 24.36 = 0.3g Mg

The ignition of Mg means that it's reacting with oxygen to form an oxide. The increase in the crucible mass after the Mg ignition is due to the addition of oxygen. However, the addition of few drops of water produces a new compound: a hydroxide. According to the oxidation state og Mg (2+), the only magnesium oxide possible is MgO. It happens because the oxidation state of oxygen in oxides is 2-. Which means that just one oxygen atom is required to electrically neutralize one magnesium atom.

We can use a conversion factor to know how much MgO is made from from 0.3 g of Mg:

$0.3g Mg$ * $\frac{16gO}{24.3gMg}$ = 0.2g O

Thereby the mass of the oxide is 0.2g O + 0.3g Mg = 0.5g MgO

We convert the mass of oxygen and magnesium to the respective amounts in moles by using conversion factors:

$0.2g O$ * $\frac{1 mol O}{16g O}$ = 0.01mol O

$0.3g Mg$ * $\frac{1mol Mg}{24.3g Mg}$ = 0.01mol Mg

The moles of MgO can be obtained from:

$0.5g MgO$ * $\frac{1mol MgO}{40.3g MgO}$ = 0.01mol MgO

To obtain the empirical formula, the amount fo moles of each elements must be divided by the smallest one, in this case, 0.01.

The result for both number of Mg atoms and O atoms is 1. This can be interpreted to mean that there is a Mg atom for each O atom forming the formula unit of the compound.

The step when water is added to the compound resulting after heating does not affect the calculations necessary for the magnesium oxide.

4 0

2 years ago

5. You are investigating an arson scene and you find a corpse in the rubble, but you suspect that the victim did not die as a re

Marina CMI [18]

Answer:

See the answer below.

Explanation:

Fire has three major components:

Heat
Smoke
Gases ( in form of CO, CO2 etc)

If the victim had died as a result of the fire, he/he would have inhaled smoke and hot gases from the fire. These components would have resulted in traces of burns and soot deposition in the trachea and lungs as well as traces of CO in the blood of the victim.

If the analysis of the victim's corpse does not reflect some of the results above, it can be effectively concluded that the victim has been dead before the fire.

<em>The single most important indicator of death by the fire would be the presence of CO in the blood of the victim's corpse. All others might be to a less significant degrees.</em>

8 0

2 years ago

Question 3<br> What part of a water molecule is the negatively charged side?

aleksandr82 [10.1K]

Answer:

The oxygen atom in water has a negative charge.

<h2>Definitions:</h2>

Polar molecule: A molecule in which the centroid of the positive charges is different from the centroid of the negative charges.

Oxygen: A colorless, odorless, gaseous element constituting about one-fifth of the volume of the atmosphere and present in a combined state in nature. It is the supporter of combustion in air and was the standard of atomic, combining, and molecular weights until 1961, when carbon 12 became the new standard. Symbol: O; atomic weight: 15.9994; atomic number: 8; density: 1.4290 g/l at 0°C and 760mm pressure.

Water: A transparent, odorless, tasteless liquid, a compound of hydrogen and oxygen, H2O, freezing at 32°F or 0°C and boiling at 212°F or 100°C. that in more or less impure state constitutes rain, oceans, lakes, rivers, etc.: it contains 11.188 percent hydrogen and 88.812 percent oxygen, by weight.

Hydrogen: A colorless, odorless, flammable gas that combines chemically with oxygen to form water: the lightest of the known element. Symbol: H; atomic weight: 1.00797; atomic number: 1; density: 0.0899 g/l at 0°C and 760 mm pressure.

Atom: Am atom is the smallest constituent particle of a chemical element which has the properties of that element. They re comprised of at least an electron and a portion, as is the case for Hydrogen. Atoms of all other elements however, contain at least one neutron.

Proton: A positively charged elementary particle that is a fundamental constituent of all atomic nuclei. It is the lightest and most stable baryon, having a charge equal in magnitude to that of the electron, a spin of 1/2, and a mass of 1.673 × 10-27kg. Symbol: P.

Electron: An elementary particle that is a fundamental constituent of matter, having a negative charge of 1.602 × 10-19 coulombs, ha mass of 9.108 × 10-31 kilograms, and spin of 1/23, and existing independently or as the component outside the nucleus of an atom.

Neutron: An elementary particle having no charge, mass slightly greater than that of a proton, and spin of 1/2: a constituent of the nuclei of all atoms except those of hydrogen. Symbol: n.

<h2>What is a negative charge?</h2>

A object has a negative charge when it consists of more electrons than protons.

With a partial positive charge on 2 Hs and a partial negative charge on oxygen, water molecules are polar molecules.

Actually, two hydrogen atoms and the core oxygen atom of water are covalently connected. Due to its greater electronegative nature than hydrogen, oxygen pulls the bound electron pair in the middle of the atom toward it.

When illustrating higher electron densities over oxygen, partial negative charge is used, whereas partial positive charge is used to illustrate lower densities over hydrogen atoms.

#SPJ2

3 0

1 year ago

Suppose of hcl and of o2 are added to an empty flask. How much will be in the flask at equilibrium?A. None. B. Some, but less th

serg [7]

This is an incomplete question, here is a complete question.

Hydrogen chloride and oxygen react to form water and chlorine, like this:

$4HCI(g)+O_2(g)\rightarrow 2H_2(g)+2CI_2(g)$

Use this chemical equation to answer the questions in the table below.

Suppose 155. mmol of HCl and 38.8 mmol of O₂ are added to an empty flask. How much HCl will be in the flask at equilibrium?

(1) None.

(2) Some, but less than 155. mmol,

(3) 155. mmol,

(4) More than 155. mmol,

Answer : The correct option is, (1) None

Explanation :

The given balanced chemical reaction is:

$4HCI(g)+O_2(g)\rightarrow 2H_2(g)+2CI_2(g)$

From the balanced chemical reaction, we conclude that

As, 4 mmole of HCl react with 1 mmoles of $O_2$

So, 155. mmole of HCl react with $\frac{155.}{4}\times 1=38.75$ mmoles of $O_2$

That means, $O_2$ is excess reagent and $HCl$ is a limiting reagent. All the moles of HCl will consume.

Hence, the correct option is, None.

7 0

3 years ago

Can one atom in this type of reaction win the "tug of war"? What might happen if it did?

Sliva [168]

Answer: YES

Explanation:

POLAR BONDS will form.

A polar bond is a covalent bond between two atoms where the electrons forming the bond are unequally distributed. This causes the molecule to have a slight electrical dipole moment where one end is slightly positive and the other is slightly negative.

5 0

2 years ago

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