Answer:
The first row fits in period 2
The second row fits in period 3
Explanation:
Elements arranged vertically in the periodic table in groups that share similar chemical properties.
Elements are also organized horizontally in rows or periods
The length of each period is determined by the number of electrons that can occupy the sublevels being filled in that period.
Answer:
NH3 < NF3 < BCl3
Explanation:
The vapour pressure of a substance has something to do with the nature of intermolecular forces between its molecules. If the molecules of a substance are held together by strong intermolecular forces, the substance will display a low vapour pressure at a given temperature and vice versa.
Ammonia has the lowest vapour pressure because of strong intermolecular hydrogen bonds that hold its molecules together.
<span>Petroleum and biomass are burned in combustion reactions, which liberate energy stored in chemical bonds. This is chemical energy. In contrast, nuclear energy comes from the conversion of mass into energy when an nuclear reaction occurs. Geothermal energy comes directly from heat sources underground, with no chemical or nuclear reactions.</span>
Answer:
Answer A
Explanation:
2 H2 + O2 = 2 H2O
knowing the mole weights of these elements shows O2 is the limiting reactant in this situation.
4 g oxygen is 4 /31.998 = .125 mole O2
We should get two times these moles of water = .250 moles
weight = .250 (1.008 * 2 + 15.999) = 4.50 gm H20 (theoretical)
....but we only got 4 gm
4/4.50 = 88.8%
We use the Boyle's law to solve this question. At constant temperature, the volume of a fixed mass of a gas is inversely proportional to its pressure. When comparing the fixed mass of gas at different conditions under this law, the expression below is used.
P₁V₁=P₂V₂
P₁=5.0 atm
P₂=7.0atm
V₁=3.5 L
V₂=V
5.0×3.5=7.0×V
V= (5.0×3.5)7.0
V=2.5 L