pressure......................................
I think the answer is the last answer at the bottom
Let's eliminate these one by one.
The first pair would not be the same, as X would most likely be in group IA, and Y would be in group VIIA, because of their tendency to gain and lose electrons.
The second pair would also violate the same rule, but X would most likely be in group IIA, and Y would most likely be in group VIA.
The third pair would not be the same, as X is most likely in group VIIA, and since Y has eight valence electrons, it is most likely a noble gas.
The final pair has X with atomic number 15, making it phosphorous. Phosphorous wants to gain 3 electrons to have a full octet of 8 outer "valence" electrons, and Y would also like to gain 3 electrons. This means it is possible that the final pair would be in the same group.
Answer:
See the answer below
Explanation:
<em>The slide could have broken due to the ramming of the objective (especially the high power objectives) into the slide on the stage of the microscope while trying to bring the object on the slide into focus.</em>
It is recommended to <u>start with the lowest objective while trying to focus a slide</u>. Thereafter, the next higher objective can be switched to and the image brought into focus once again. This can be repeated until the desired magnification of the image is reached.
However, <u>at higher objective powers, the coarse adjustment knob should be avoided </u>to avoid the objectives touching/breaking the slide. Instead, the fine adjustment knob should be used.
Hence, the breaking of the slide in the illustration could have been due to the use of the coarse adjustment knob at higher objective powers and the ramming of the objective into the slide.
The balanced chemical reaction is
NaCl + AgNO3 --> AgCl + NaNO3
To find out if precipitation will occur, we need to calculate the number of
moles acting in the chemical reaction
But Molarity, M=nV, where n is the number of moles and V is the volume in
litres. So n = M/V
number of moles of AgNo3 = 0.02/500 * 10^(-3)
n= 0.04
While n of Sodium chloride = 0.01/0.5 = 0.2. Since there is excess sodium chloride ( twice as much) precipitation will not occur. 2NaCl + 2AgNO3 -->
2AgCl + 2NaNO3. The reaction requires one and not two moles of AgNo3 as evident from the number of moles which is 0.04