Answer: Gold act as cathode.
Explanation:
Standard potential for an electrochemical cell is given by:
= standard electrode potential =
The 
values have to be reduction potentials.
Reduction potentials for given elements
The element Be with negative reduction potential will lose electrons undergo oxidation and thus act as anode.The element Au with positive reduction potential will gain electrons undergo reduction and thus acts as cathode.
Cathode : 
Anode : 
Thus gold act as cathode.
Answer:
Attraction
(e-) ---> <--- (H+)
Repulsion:
<---(e-) (e-)-->
Neutral:
(e-) (Helium)
Explanation:
Accordingly to coulomb's law:
In the attraction, the hydrogen without an electron has a positive charge and needs to be fulfilled with a negative charge found in an eletron.
In the repulsion, both electrons has the same charge and repulse each other.
In the neutral case, the Helium is highly stable therefore the electron is not attracted.
Mass of the gas m = 1.66
The calculated temperature T = 273 + 20 = 293
We have to calculate molar mass to determine the gas
Molar Mass = mRT / PV
M = (1.66 x 8.314 x 293) / (101.3 x 1000 x 0.001)
M = 4043.76 / 101.3 = 39.92 g/mol
So this gas has to be Argon Ar based on the molar mass.
Answer:
An atom has a nucleus, made up protons and neutrons, which is surrounded by a cloud of electrons.
Explanation:
An atom is the smallest indivisible part of any element that takes place in a chemical reactions.
These are the fundamental building blocks of every element and even compounds.
- There are three known subatomic particles found within an atom.
- Electrons are the negatively charged particles in an atom
- Protons are the positively charged particles of an atom
- Neutrons do not carry any charges.
Both protons and neutrons are located within the tiny space called nucleus at the center of an atom.
Electrons moves round in orbitals at the spaces outside of the nucleus.
Answer: CrO₄⁻ and Ba²⁺
Explanation:
1) Chemical equation given:
2H⁺ + CrO₄⁻ + Ba²⁺ + 2OH⁻ → Ba²⁺ + CrO₄⁻ + 2H₂O
2) Analysis
That is an oxidation-reduction equation (some species are been oxidized and others are being reduced).
The given equation is known as total ionic equation, because it shows all the species as ions that are part of the reaction.
2) Specator ions
Spectator ions are the ions that do not change their oxidation state and are easily identified as they are the same in the reactant and product sides.
Here the ions that are the same in the reactant and product sides are:
CrO₄⁻ and Ba²⁺
3) Addtitional explanation.
Once you identify the spectator ions you can delete them from the equation to obtain the net ionic equation , which in this case turns to be:
2H⁺ + 2OH⁻ → 2H₂O
But this is not part of the question; it is some context to help you understand the use of the spectator ions concept.
