Answer:
The correct answer is option B.
Explanation:
Exothermic reactions are are those reaction which heat evolved and released into the surroundings. Due to this release of heat temperature of the surrounding increases.
Endothermic reactions are are those reaction which heat absorbed from the surroundings. Due to this absorption of heat temperature of the surrounding decreases.
Decomposition reaction : the reaction in which single compound broke down into its smaller compounds or elements.
Combination reaction : The reaction which two or more compounds combine together to give single compound.
In the given reaction, heat is provided or it is absorbed by the calcium carbonate to break down into calcium oxide and carbon dioxide.
Hence, endothermic decomposition reaction.
(a) HClO2 <=> H+ + ClO2-
Equilibrium expression is
Keq = [H+][ClO2-] / [HClO2]
(b) HNO2 <=> H+ + NO2-
Equilibrium expression is
Keq = [H+][NO2-] / [NO2]
(b) HNO <=> H+ + IO-
Equilibrium expression is
Keq = [H+][IO-] / [IO]
6.02214086 x 10^23 mol^-1
Answer:
4.2 moles of sodium cyanide (NaCN) would be needed to produce 2.1 moles of sodium sulfate (Na₂SO₄).
Explanation:
The balanced reaction is:
H₂SO₄ + 2 NaCN → 2 HCN + Na₂SO₄
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 are necessary:
- H₂SO₄: 1 mole
- NaCN: 2 moles
- HCN: 2 moles
- Na₂SO₄: 1 mole
Then you can apply the following rule of three: if by stoichiometry to produce 1 mole of sodium sulfate 2 moles of sodium cyanide are necessary, then to produce 2.1 moles of sodium sulfate how many moles of sodium cyanide are necessary?
amount of moles of sodium cyanide= 4.2 moles
<u><em>4.2 moles of sodium cyanide (NaCN) would be needed to produce 2.1 moles of sodium sulfate (Na₂SO₄).</em></u>
Answer:
Cell phones use radio waves to communicate with cell towers, and these waves have wavelengths of approximately 10-1000 m, which are much too large to be ionizing. WiFi actually operates at quite precise frequencies, either 2.4 GHz or 5 GHz, which correspond to wavelengths of either 12 cm or 6 cm.
Explanation:
When the mobile phone is turned on, it emits radio waves that consist of radio frequency (RF) energy—a form of electromagnetic radiation moving at the speed of light. It works by transmitting radio wave signals to (and receiving these from) nearby base stations.