Name three things that are matter and why

How many grams of oxygen is needed to completely react with 9.30 moles of aluminum

Orlov [11]

Balanced chemical equation:

* moles of oxygen

4 Al + 3 O2 = 2 Al2O3

4 moles Al -------------- 3 moles O2
9.30 moles Al ---------- moles O2

moles O2 = 9.30 * 3 / 4

moles O2 = 27.9 / 4 => 6.975 moles of O2

Therefore:

Molar mass O2 = 31.9988 g/mol

n = m / mm

6.975 = m / 31.9988

m = 6.975 * 31.9988

m = 223.19 of O2

5 0

3 years ago

I found a type of rock in the woods it's kinda rough black with some purple like a lavender purple and i can break it into piece

Vesna [10]

It could be a lump of coal.
Since you can break pieces off, maybe charcoal ... the real thing, not a "briquet".
Do your hands get all black when you handle it ?

5 0

4 years ago

Classify these substances? More than one answer may apply in each case.

dalvyx [7]

Answer:

N2 element, pure substance

O2 element, pure substance

N2O Compound, pure substance

Air (mostly N2 and O2 ) homogeneous mixture

Explanation:

N2, Nitrogen is known as the chemical element that is characterized by having atomic number 7 and that is symbolized by the letter N, in its molecular version, it is recognized as N2.

O2, Oxygen is the chemical element of atomic number 8, this molecular form is composed of two atoms of this element.

A chemical element is a type of matter, consisting of atoms of the same class.

N2O, Nitrous oxide is formed by the union of two molecules of nitrogen and one of oxygen, which is considered a chemical compound since it is a substance formed by the chemical combination of two different elements of the periodic table.

A pure substance is one that cannot change state or divide into other substances, except for a chemical reaction.

Air (mostly N2 and O2 ), it is a homogeneous mixture of gases that constitutes the earth's atmosphere. A homogeneous mixture is a type of mixture in which its components are not distinguished and in which the composition is uniform and each part of the solution has the same properties.

3 0

3 years ago

What is the change in internal energy for each of the following situations? 1. q-7.9 J out of the system and w 3.6 J done on the

adoni [48]

Answer:

A i. Internal energy ΔU = -4.3 J ii. Internal energy ΔU = -6.0 J B. The second system is lower in energy.

Explanation:

A. We know that the internal energy,ΔU = q + w where q = quantity of heat and w = work done on system.

1. In the above q = -7.9 J (the negative indicating heat loss by the system). w = 3.6 J (It is positive because work is done on the system). So, the internal energy for this system is ΔU₁ = q + w = -7.9J + 3.6J = -4.3 J

ii. From the question q = +1.5 J (the positive indicating heat into the system). w = -7.5 J (It is negative because work is done by the system). So, the internal energy for this system is ΔU₂ = q + w = +1.5J + (-7.5J) = +1.5J - 7.5J = - 6.0J

B. We know that ΔU = U₂ - U₁ where U₁ and U₂ are the initial and final internal energies of the system. Since for the systems above, the initial internal energies U₁ are the same, then we say U₁ = U. Let U₁ and U₂ now represent the final energies of both systems in A i and A ii above. So, we write ΔU₁ = U₁ - U and ΔU₂ = U₂ - U where ΔU₁ and ΔU₂ are the internal energy changes in A i and A ii respectively. Now from ΔU₁ = U₁ - U, U₁ = ΔU₁ + U and U₂ = ΔU₂ + U. Subtracting both equations U₁ - U₂ = ΔU₁ - ΔU₂

= -4.3J -(-6.0 J)= 1.7 J. Since U₁ - U₂ > 0 , U₂ < U₁ , so the second system's internal energy increase less and is lower in energy and is more stable.

8 0

3 years ago

Which of the following would be investigated in reaction stoichiometry? Group of answer choices The types of bonds that break an

DENIUS [597]

Answer:

The mass of potassium required to produce a known mass of potassium chloride

Explanation:

Stoichiometry deals with the relationship between amount of substances, mass of substances or volume of substances required in a chemical reaction. Stoichiometric relationships may involve reactants alone or reactants and products. These relationships are normally in the form of simple proportion.

A typical example is our answer option, the mass of potassium required could be used to determine the mass of potassium chloride produced after a balanced reaction equation is written.

7 0

3 years ago