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3 years ago

A substance that cannot be broken down into other substances by ordinary chemical procedures is an

1 answer:

5 0

An ELEMENT is a substance that cannot be broken down into other substances by ordinary chemical procedures. Some easy examples would be: gold, iron, carbon, hydrogen, oxygen, nitrogen.

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Ar (g) is placed in a 3.80 L container at 320 K. The gas pressure is 0.496 atm.

nata0808 [166]

Answer:

PV=nRt

Therefore n(number of moles)=PV/RT

=>(0.49×3.80)/(0.08206×320)

Therefore Number of moles is = 0.071mols

Explanation: By using the Real gas equation..

PV=NRT .

We can solve for the number of moles of Ar by making N the subject..

Always make sure you pressure is In atm, your Volume is in Litres and temperature in degree Kelvin.

Also Recall the universal gas constant R used in this type of questions which is 0.08206.

Hence l, by making N the subject we get our answer as

3 0

4 years ago

Balance the following oxidation-reduction reactions, which take place in acidic solution, by using the "half-reaction" method.

LuckyWell [14K]

First identify which is being oxidized and reduced. In this case, the Mg is being oxidized and the Hg is being reduced.

Mg --> Mg+2

Hg+2 --> Hg+1

Then you have to balance each half reaction first with electrons before adding them together in one equation

$Mg$ ⇒ $Mg^{+2} + 2e^{-1}$

and

$2Hg^{+2} + 2e^{-1}$ ⇒ $Hg_{2} ^{+2}$

and then combine them together to form

$Mg + 2 Hg^{+2} + 2e$ ⇒ $Mg^{+2} + 2e ^{-} + 2 Hg^{+1} + 2 e^{-}$

It isn't necessary to keep the electrons but its essential to know how many there are in order to know how many are in the equation in order to calculate the reaction energy. Note: Add H+ and H2O to balance the H's and O's in acidic solution if needed.

8 0

4 years ago

Write the balanced equation for a reaction between aqueous nitric acid (HNO3) and solid lithium metal (this is a single replacem

Lemur [1.5K]

Answer: The equation is given below.

Explanation:

Single replacement reactions are the chemical reactions in which more reactive metal displaces a less reactive metal from its chemical reaction. General equation for these reactions is given by the equation:

$A+BC\rightarrow AC+B$

Metal A is more reactive than metal B.

The reactivity of metals is judged with the help of reactivity series. In this series, the metals lying above are more reactive than the metals which lie below in the series.

For the reaction of solid lithium metal and nitric acid, the equation follows:

$3Li(s)+4HNO_3(aq.)\rightarrow 3LiNO_3(aq.)+2H_2O(l)+NO(g)$

This is a type of single replacement reaction because Lithium (more reactive metal) is replacing Hydrogen (less reactive metal) from the chemical reaction.

3 0

3 years ago

Which of the following statements is incorrect? A. Molecular mass is expressed in atomic mass units. B. Formula mass compares th

n200080 [17]

Answer:

The incorrect statement is the choice C. Atomic mass has units of grams per atom.

Explanation:

1) Choice A. Molecular mass is expressed in atomic mass units.

Correct. Atomic mass units (a.m.u) is the standard unit used to express the mass of the atoms and the molecules.

Since, one atom, molecule, or formula unit is a tiny amount of material, it has a ver, very low mass, and the unit mass of a molecule is referred to one mole (6.022 × 10²³ units).

2) Choice B. Formula mass compares the mass of one formula unit of a substance to the mass of one atom of carbon-12.

Correct. The masses of atoms and compounds are referred to a standard. Such standard is the carbon-12 atom. This is, the cabon-12 atom was selected as the standard and its exact mass is 12 a.m.u.

3) Choice C. Atomic mass has units of grams per atom.

Incorrect. Atomic mass is the mass of the atoms, but, since, the mass of one atom is so small, the atomic mass is referred to one mole. Hence, the atomic mass has units of grams per mole.

4) Choice D. Both molecular mass and formula mass use carbon-12 as a reference standard.

Correct. As stated when explaining the option B, the mass of atoms, molecules, and formula units are referred to carbon-12 standard.

5) Choice E. Sodium chloride, an ionic compound, is said to have a formula weight, but not a molecular weight.

Correct. The reason is that ionic compounds form large structures (crystals) and, since there is not such thing as one molecule of them, they are said to have formula weight (or mass) but not a molecular weight.

The name molecules is reserved for covalent compounds, where you can formally identify molecules. E.g. Water is a molecular compound, and each molecule has molecular formula H₂O, whose mass is the molecular mass.

7 0

4 years ago

Which atomic property is different in each isotope of an element?

slava [35]

Mass number...use da textbook bra

6 0

4 years ago