440 cause mass cant be created or destroyed
Answer:
B) The term "inert" was dropped because it no longer described all the group 8A elements.
Explanation:
Inert elements in chemistry simply refers to elements that are chemically inactive and are not expected to form any compounds. this is the general belief for the group 8 elements as they all have complete duplet/octet configurations (and ideally, they ought to be very stable with no tendency to form compounds by participating in the loss and gain of electrons). However the discovery of compounds like xenon tetrafluoride (XeF4) proved this to be wrong.
Again, the reason the term - inert gses was droppedis beacause this term is not strictly accurate because several of them do take part in chemical reactions.
After dropping the term - Inert gases, they are now referred to as noble gases.
Answer: Beta particles cannot penetrate very far into solids because they <span><u>have no mass.
</u>
Reason<u>:
</u>Penetrating power of particle depending upon the velocity and mass of particle. Greater the mass and velocity. Higher will be the penetrating power. In case of Beta particles, they are electrons. Mass of an electron is 9.1 X </span>
Kg. Due to such negligible mass, they have very low penetrating power. <span /><span><u>
</u></span>
Here are 3 main types of models are ( Physical, Mathematical, and Conceptual. Models have limitations but are useful and can be changed based on a new evidence.
First step is to balance the reaction equation. Hence we get
P4 + 5 O2 => 2 P2O5
Second, we calculate the amounts we start with
P4: 112 g = 112 g/ 124 g/mol – 0.903 mol
O2: 112 g = 112 g / 32 g/mol = 3.5 mol
Lastly, we calculate the amount of P2O5 produced.
2.5 mol of O2 will react with 0.7 mol of P2O5 to produce 1.4
mol of P2O5.
This is 1.4 * (31*2 + 16*5) = 198.8 g
