The answer is (B) Electrons are distributed around the nucleus and occupy almost all the volume of the atom.
(a) Balance the above redox reaction.
(b) Determine the concentration of H2O2 solution in molarity if 10.00 mL of this solution requires 20.00 mL of 1.5 M MnO4− for a complete reaction.
Answer:
A)
B) 7.5 molar
Explanation:
A)Reduction
Oxidation
Multiplying the oxidation reaction by 5/2 and adding it to the reduction equation:
+
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B) 10 ml = 0.01 L
20 ml = 0.02 L
mol of MnO4− = molarity*volume = 1.5*0.02 = 0.03
1 mol of MnO4− reacts with 5/2 mol of H2O2, then:
mol of H2O2 = 0.03*5/2 = 0.075
molarity = mol/volume = 0.075/0.01 = 7.5 molar
Answer:
The correct answer is B) the C=O bond is polar; the O atom bears a partial negative charge.
Explanation:
In a C=O bond, the oxygen (O) atom is more electronegative than the carbon (C) atom. Electronegativity is the ability of an atom to attract electrons towards itself in a chemical bond. Oxygen has a higher electronegativity than carbon, so it pulls the shared electrons in the C=O bond closer to itself.
As a result, the oxygen atom gains a partial negative charge (δ-) because it has a higher electron density around it, while the carbon atom gains a partial positive charge (δ+) because it has less electron density around it.
This uneven distribution of electron density in the C=O bond leads to polarity, making the bond polar. The oxygen atom, being more electronegative, attracts the shared electrons more strongly, creating a partial negative charge on the oxygen atom and a partial positive charge on the carbon atom.
In summary, the C=O bond is polar, and the oxygen atom bears a partial negative charge (δ-).
Answer:
12.58 g/cm³
Explanation:
V = 7×4×1 = 28cm³
ρ = m/V = 352/28 ≈ 12.58 g/cm³
Potassium sulphide has the chemical formula S .
A chemical formula is a phrase that lists the constituent parts of a compound together with their relative proportions. No subscript is used if there is just one atom of a certain kind.
Alkali metals in Group 1A produce plus-one ions because they wish to give up their valence electron in their outer shell.
In order to have a complete octet in its outermost shell, sulphur, which is found in the chalcogens, needs to gain two electrons.
Thus, Potassium sulphide has the chemical formula S .
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# SPJ2
Answer: The mass of unknown acid needed is 0.230 grams
Explanation:
To calculate the number of moles for given molarity, we use the equation:
Molarity of NaOH solution = 0.100 M
Volume of solution = 15.00 mL = 0.015 L (Conversion factor: 1 L = 1000 mL)
Putting values in above equation, we get:
The chemical reaction for the reaction of KHP and NaOH follows
By Stoichiometry of the reaction:
1 mole of NaOH reacts with 1 mole of KHP.
So, 0.0015 moles of NaOH will react with = of KHP
Moles of KHP = 0.0015 moles
Molar mass of KHP = 204.22 g/mol
Putting values in above equation, we get:
We are given:
Mass of unknown acid = 75 % of Mass of KHP
So, mass of unknown acid =
Hence, the mass of unknown acid needed is 0.230 grams
red dwarf
white dwarf
pulsar
black hole
Answer:
The correct answer is pulsar.
Explanation:
Protostar : Its a young star with contracting mass which gains mass from its parent molecular cloud. At this stage fusion process does not start.
Red dwarf: A star having lower surface temperature , luminosity, mass and size than of the sun.
White dwarf : its an ultimate stage for an average mass star like sun . its a small dense star with size relatively equal to planet.
Pulsar : A rotating neutron star that emits beam of radio waves and other electromagnetic radiations.
Black hole: It is region of space time with very strong gravitational pull that even smallest particle or electromagnetic wave is incapable to escape it.