M=D*V
D=620 g/cm³
V=75 cm³
m= 620 g/cm³ * 75 cm³=46500 g
m=46500g
Answer:
Period 4
Explanation:
Given the electronic configuration of the element;
= Is² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p¹
The period of the element is determined by the highest coefficient in the electronic configuration.
For this given configuration (Is² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p¹), "4" is the highest coefficient and the element will certainly belong to period 4 in the periodic table.
To test if the prediction is correct:
Total number of electrons in the given element = 2+2+6+2+6+10+2+1 = 31
The element with atomic number of 31 = Gallium (Ga). (This element belong to period 4).
First, we calculate the number of moles of each reactant using the formula:
Moles = mass / molecular weight
CaO:
Moles = 7.15/56 = 0.128
Water:
Moles = 152/18 = 8.44
The reaction equation shows that the reactants must be present in an equal number of moles, so CaO will be the limiting reactant and 0.128 mole of calcium hydroxide will form.
The energy released is given by:
Heat of reaction * number of moles
= -64.8 * 0.128
= -8.29 kJ
8.29 kJ of energy will be released
Answer: The statement which could possibly not be true is C -" Liquid X can exist as a stable phase at 25°C, 1atm."
Explanation:
Triple point is the point where a substance co-exist as solid liquid and gas. At any point other than the triple point, the substance exist as a single phase substance.
As shown in the diagram, Liquid cannot exist as a stable phase at 1atm( below the the triple point pressure of 2atm) as the liquid can only exist beyond the pressure of triple point.
The answer is D. Column chromatography has a mobile and stationary phase. The stationary phase is made of solid beads with pores of particular sizes depending on the mixture being processed. The mobile phase is usually a solvent that carries the mixture down the column as the different components of the mixtures separate. The different elements, due to differences in sizes of their molecules, pass through the pores of the beads at different rates hence elute from the columns differentially.