How many days are required for 200. grams of radon-222 to decay to 50.0 grams?(1) 1.91 days (3) 7.64 days(2) 3.82 days (4) 11.5 days
Answers
The answer is: 3) 7.64 days.
The most stable isotope of radon (Rn) is radon-222 with a half-life of 3.82 days.
After first half life (3.82 days) = 0.5 · 200 g.
After first half life (3.82 days) = 100 g of radon-222.
After second half life (7.64 days) = 0.5 · 100 g.
After second half life (7.64 days) = 50 g of radon-222.
Half-life is the time required for a quantity (in this example number of radioactive nuclei of radon-222) to reduce to half its initial value and is independent of initial concentration.
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The concentration of hydrogen peroxide (H2O2) can be determined by titrating it with an acidified MnO4− solution. The following is an unbalanced equation. MnO4− (aq) + H2O2 (aq) → O2 (g) + Mn2+ (aq)(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.
Liquid petrol does not ignite spontaneously in air
In the thermal decomposition of copper carbonate, the black solid left behind weights less than the original copper carbonate . Why?
Answers
Answer : Option B) Hydrogen
Explanation :
All fossil fuels contains hydrocarbons in it. Amongst the given options hydrogen is the correct answer. Except that it contains carbon in it. Hydrocarbons are those class of compounds which contains hydrogen and carbon as element in it.
They are considered to be good fuels because they naturally bring out complete combustion as they contain hydrogen and carbon in its compound form.
B: H2o
C: HI
D: C3H8
Answers
Hydrogen bonds take place between the molecules of H2O.
• Hydrogen bonding takes place only in the molecules where the hydrogen is covalently bonded to nitrogen, oxygen, or fluorine.
• The electronegativity of these three elements is so much that they withdraw most of the electron density in the covalent bond with hydrogen, leaving the atom of hydrogen extremely electron-deficient.
• In the molecule of water, the nucleus of oxygen with +8 charges attracts electrons better than the nucleus of hydrogen with its +1 charge.
• The hydrogen atoms apart from being covalently bonded with the atoms of oxygen are also attracted towards the oxygen atoms nearby. This attraction is the basis of the hydrogen bonds.
Thus, option B, H2O is correct.
To know more about:
Final answer:
Hydrogen bonds can be found between molecules of H2O (water). This is due to the fact that water has a highly electronegative oxygen atom and hydrogen atoms capable of forming a dipole interaction, thereby constituting a hydrogen bond.
Explanation:
Hydrogen bonds can be found between molecules of substance B: H2O, also known as water. Hydrogen bonding occurs when a highly electronegative atom such as Oxygen (O), Nitrogen (N), or Fluorine (F) is involved and there is a hydrogen atom attached to these. In the case of water, there are two hydrogen atoms bonded to a single oxygen atom, which is highly electronegative. These specific features allow for the formation of a relatively strong dipole interaction, called a hydrogen bond, between separate water molecules.
Learn more about Hydrogen Bonds here:
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Answers
Taking into account the reaction stoichiometry, 51.84 grams of HCl is required to react completely with 12.8 g of aluminum to produce aluminum chloride and hydrogen gas.
Reaction stoichiometry
In first place, the balanced reaction is:
2 Al + 6 HCl → 2 AlCl₃ + 3 H₂
By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:
- Al: 2 moles
- HCl: 6 moles
- AlCl₃: 2 moles
- H₂: 3 moles
The molar mass of the compounds is:
- Al: 27 g/mole
- HCl: 36.45 g/mole
- AlCl₃: 133.35 g/mole
- H₂: 2 g/mole
Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:
- Al: 2 moles ×27 g/mole= 54 grams
- HCl: 6 moles ×36.45 g/mole= 218.7 grams
- AlCl₃: 2 moles ×133.35 g/mole= 266.7 grams
- H₂: 3 moles ×2 g/mole= 6 grams
Mass of HCl required
The following rule of three can be applied: If by reaction stoichiometry 54 grams of Al react with 218.7 grams of HCl, 12.8 grams of Al react with how much mass of HCl?
mass of HCl= 51.84 grams
Finally, 51.84 grams of HCl is required to react completely with 12.8 g of aluminum to produce aluminum chloride and hydrogen gas.
Learn more about the reaction stoichiometry:
next, take 12.8g/mr of aluminium
this will give u the mols of aluminium
next, take the ratio of HCL and Al, compare and find the mols of HCL.
take the mols of HCL/mr of HCL to give u mass
doneee
Answers
Explanation:
Sodium has atomic number of 11 with electronic configuration of :
Sodium loose it single electron to attain stability of noble gas configuration. While this process electron gets removed from the outer shell of the sodium atom and it gains positive charge of +1.
(Ionization)
Answers
Answer:
Cu,Sn,Pb,Mg,Ca.Na,K
Explanation:
Answers
The complete ionic equation is as follows: H+ + I
+K
+OH
H₂O
+K
+I
What is ionic equation?
Ionic equation is defined as a chemical equation which represents electrolytes in aqueous solutions and are expressed as dissociated ions. Ions present in aqueous solutions are stabilized by ion dipole interactions with the water molecules which are present.
An ionic equation can be written for any electrolyte which dissociates and reacts with the polar solvent. In a balanced ionic equation , number and type of atoms on each sides of reaction arrow are same. Even the net charge on both sides of the arrow is same.
Strong acids and bases exist as dissociated ions present in the solution and are written in forms of ions in ionic equation.Weak acids and bases do not dissociate completely and hence are written in the form of molecular formula.
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H+(aq) + I-(aq) + K+(aq) + OH-(aq) ------> H2O(l) + K+(aq) + I-(aq)
H+(aq) + OH-(aq) ----> H2O(l)