Answer:
Three primary reasons. First, there is simply more water-covered places than dry ground places for the animals and plants to have lived. Second, the seas are much more crowded with the kinds of life that leave fossils than the land is. Third, the process that form fossils work very well under water.
Explanation:
Answer:
X= Be
Y= B
Z=O
Explanation:
From the description of the compound XCl2, among the options listed only beryllium can form such compound with three lone pairs in the two chlorine atoms and no lone pair on the central atom X.
From the description of YCl3, only Boron among the options listed can form such a compound with no lone pair on the central atom and three lone pairs on each of the chlorine atoms.
From the description of ZCl2, only oxygen forms the compound OCl2 among the elements listed where oxygen possesses two lone pairs and each chlorine atom possesses three lone pairs each.
Answer:
The upper and lower limits for the room-temperature thermal conductivity of a magnesium oxide material having a volume fraction of 0.10 of pores that are filled with still air are
Ku = 38.252 W/mK
K lower = 0.199 W/mK
Explanation:
As we know
Ku = Vp * Kair + Vmagnesium * K metal
Ku = 0.10 *0.02 + (1-0.25) * 51
Ku = 38.252 W/mK
The lower limit
K lower = Kmetal* Kair/( Vp * Kmetal + Vmetal * K air)
K lower = (0.02*51)/(0.10*51 + 0.90 * 0.02)
K lower = 0.199 W/mK
Answer:
volume of the container will decreases if pressure increases.
Explanation:
According to Boyle's law:
Pressure is inversely proportional to volume which means if pressure of a gas increases the volume of the gas will decreases as gas molecules will collide and come closer forcefully so volume will decreases. And its formula for determining volume and pressure is:
<em>PV=nRT</em>
where "R" is a ideal gas constant
"T" is temperature and
"n" is number of particles given in moles while "V" is volume and "P" is pressure.
Answer:
The mass of 8.250 moles of Cu2O is 1180.5g
Explanation:
HOW TO CALCULATE MASS OF A SUBSTANCE:
- The mass of a substance can be calculated by multiplying the number of moles in the substance by its molar mass as follows:
Mass (g) = no. of moles (mol) × molar mass (g/mol)
- Molar mass of copper (I) oxide (Cu2O) = 63.5(2) + 16 = 143.09 g/mol
Mass of Cu2O = 8.250 mol × 143.09 g/mol
Mass of Cu2O = 1180.5 g
Therefore, the mass of 8.250 moles of Cu2O is 1180.5 g.
