Answer:
The answer is B. Van der Waals forces are weaker than ionic and covalent bonds.
Explanation:
In general, if we arrange these molecular forces from the strongest to weakest, it would be like this:
Covalent bonds > Ionic bonds > Hydrogen bonds > Dipole-Dipole Interactions > Van der Waals forces
Covalent bonds are known to have the strongest and most stable bonds since they go deep and into the inter-molecular state. A diamond is an example of a compound with this characteristic bond.
Ionic bonds are the next strongest molecular bond following covalent bonds. This is due to the protons and electrons causing an electro-static force which results to the strong bonds. An example would be Sodium Chloride (NaCl), which when separated is Na⁺ and Cl⁻.
Van der Waals forces, also known as Dispersion forces, are the weakest type of molecular bonds. They are only formed through residual molecular attractions when molecules pass by each other. It doesn't even last long due to the uneven electron dispersion. It can be made stronger by adding more electrons in the molecule. This kind of molecular bonds appear in non-polar molecules such as carbon dioxide.
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After three half lives have passed, there would be only 12.5 percent of the original amount of a radioactive parent isotope that will remain. Half life is the time needed for a certain amount of a substance to be half its initial amount. It is a common term used in nuclear chemistry describing how fast radioactive substances undergo decay. One half life would correspond to only 50% would be left. Two half lives would be 25% only of the original value. Three half lives would be 12.5%. Four half lives would be 6.25% of the initial value. So on and so forth.
Answer:
Mass = 42.8g
Explanation:
4 NH 3 ( g ) + 5 O 2 ( g ) ⟶ 4 NO ( g ) + 6 H 2 O ( g )
Observe that every 4 mole of ammonia requires 5 moles of oxygen to obtain 4 moles of Nitrogen oxide and 6 moles of water.
Step 1: Determine the balanced chemical equation for the chemical reaction.
The balanced chemical equation is already given.
Step 2: Convert all given information into moles (through the use of molar mass as a conversion factor).
Ammonia = 63.4g × 1mol / 17.031 g = 3.7226mol
Oxygen = 63.4g × 1mol / 32g = 1.9813mol
Step 3: Calculate the mole ratio from the given information. Compare the calculated ratio to the actual ratio.
If all of the 1.9831 moles of oxygen were to be used up, there would need to be 1.9831 × 4 / 5 or 1.5865 moles of Ammonia. We have 3.72226 moles of ammonia - Far excess. Because there is an excess of Ammonia, the Oxygen amount is used to calculate the amount of the products in the reaction.
Step 4: Use the amount of limiting reactant to calculate the amount of H2O produced.
5 moles of O2 = 6 moles of H2O
1.9831 moles = x
x = (1.9831 * 6 ) / 5
x = 2.37972 moles
Mass of H2O = Molar mass * Molar mass
Mass = 2.7972 * 18
Mass = 42.8g
Sir Joseph John Thomson OM PRS (18 December 1856 – 30 August 1940) was a British physicist and Nobel Laureate in Physics, credited with the discovery of the electron, the first subatomic particle to be discovered.