Answer:
In 1897, the British physicist J. J. Thomson (1856–1940) proved that atoms were not the most basic form of matter. He demonstrated that cathode rays could be deflected, or bent, by magnetic or electric fields, which indicated that cathode rays consist of charged particles (Figure 2.2.2 ). More important, by measuring the extent of the deflection of the cathode rays in magnetic or electric fields of various strengths, Thomson was able to calculate the mass-to-charge ratio of the particles. These particles were emitted by the negatively charged cathode and repelled by the negative terminal of an electric field. Because like charges repel each other and opposite charges attract, Thomson concluded that the particles had a net negative charge; these particles are now called electrons. Most relevant to the field of chemistry, Thomson found that the mass-to-charge ratio of cathode rays is independent of the nature of the metal electrodes or the gas, which suggested that electrons were fundamental components of all atoms.
Explanation:
Answer: 22 kJ amount of energy is released in the following reaction.
Explanation: There are two types of reaction on the basis of amount of heat absorbed or released.
1. Endothermic reactions: These are the type of reactions in which reactants absorb heat to form the products. The energy of the reactants is less than the energy of the products.
2. Exothermic reactions: These are the type of reactions in which heat is released from the chemical reactions. The energy of the products is less than the reactants.
Sign convention for
: This value is negative for exothermic reactions and positive for endothermic reactions.
For the given chemical reaction,
Energy of the products is less than the energy of the reactants, Hence, this reaction will be a type of exothermic reaction and energy will be released during this chemical change.
Amount of energy released = (350 - 372) kJ = -22kJ
Negative sign symbolizes the energy is being released. So, 22 kJ amount of energy is released in the following reaction.
Neither of them are used in magnets they don’t attract metal
Answer: last option, what came before the big bang?
Explanation:
The big bang theory states that the universe started as a dense nucleus of matter: a huge amount of matter concentrated in a tiny spot.
This is the conclusion of equations and evidences that prove that the universe has been and continuous to expand: since it has been expanding, there was a moment when it was as small and dense as it is possible.
So, the expansion is the result of violent explosion.
The time during which the expansion has been happening (this is how long ago the big bang occured) has been estimated thanks the the observation of the speed of recesion of the galaxies, but nothing can be told about what came before the bing bang occured.