Answer:
0.241 × 10³⁰ molecules
Explanation:
Given data:
Mass of Cr(HCO₃)₃ = 9.273 × 10⁷ g
Number of molecules = ?
Solution:
Number of moles = 9.273 × 10⁷ g/ 235 g/mol
Number of moles = 0.04× 10⁷ mol
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
For example,
18 g of water = 1 mole = 6.022 × 10²³ molecules of water
1.008 g of hydrogen = 1 mole = 6.022 × 10²³ atoms of hydrogen
For 0.04× 10⁷ moles of Cr(HCO₃)₃:
0.04× 10⁷ moles × 6.022 × 10²³ molecules / 1 mol
0.241 × 10³⁰ molecules
Given reactions:
(A) 6CO2(g) + 6H2O(l) + sunlight → C6H12O6(aq) + 6O2(g)
(B) 2H2(g) + O2(g) → 2H2O(g) + energy
Exothermic reactions are those which proceed with the release of heat/energy. In contrast, endothermic reactions proceed with the absorption of energy in the form of heat or light.
Since reaction A required sunlight, it is endothermic. Reaction B releases energy, hence exothermic
Ans: (B)
A is endothermic
B is exothermic
Answer:
The person’s kinetic energy is 1,025 J
Explanation:
Kinetic energy is a form of energy. It is defined as the energy associated with bodies that are in motion and this energy depends on the mass and speed of the body.
Kinetic energy is defined as the amount of work necessary to accelerate a body of a given mass and in a position of rest, until it reaches a given speed. Once this point is reached, the amount of accumulated kinetic energy will remain the same unless there is a change in speed or the body returns to its state of rest by applying a force.
Kinetic energy is represented by the following formula:
where Ec is kinetic energy, which is measured in Joules (J), m is mass measured in kilograms (kg), and v is velocity measured in meters over seconds (m/s).
In this case:
- v= 5
Replacing:
Solving:
Ec= 1,025 J
<u><em>The person’s kinetic energy is 1,025 J</em></u>
Answer:
The substances made from polyvinyls are generally brittle and hard. This property prevails because the polymer strands present in the polyvinyls form a very regular and well-organized packing composition in the solid-state. The Van der Waals associations between the strands make the substance brittle. To make the substance soft and suitable to use as a raincoat, the incorporation of small molecules is done within the molten polymer before the hardening of the plastic.
These polymer strands act as plasticizers and prevent the strands of polymer from forming a hard and brittle conformation.
