Answer:
O, S, Se, Te, Po
Explanation:
Oxygen, sulphur, selenium, tellurium and polonium are all members of group sixteen. The elements in group sixteen all possess six electrons in their outermost shell. Recall that an atom is said to stable if it contains eight electrons in its outermost shell. This is also referred to as the octet rule. Hence atoms of elements obey the octet rule when they combine to form compounds with eight electrons present on the outermost shell of each atom.
Having six electrons on their outermost shell implies that they need to gain two electrons by bonding to other atoms of other elements. Two examples will suffice here.
Water is formed when an oxygen atom shares an electron with each hydrogen atoms.
Hydrogen sulphide is formed when sulphur share two electrons with two hydrogen atoms. Hence the answer.
Answer:
ΔH0reaction = [ΔHf0 CO2(g)] - [ΔHf0 CO(g) + ΔHf0 O2(g)]
Explanation:
Chemical equation:
CO + O₂ → CO₂
Balanced chemical equation:
2CO + O₂ → 2CO₂
The standard enthalpy for the formation of CO = -110.5 kj/mol
The standard enthalpy for the formation of O₂ = 0 kj/mol
The standard enthalpy for the formation of CO₂ = -393.5 kj/mol
Now we will put the values in equation:
ΔH0reaction = [ΔHf0 CO2(g)] - [ΔHf0 CO(g) + ΔHf0 O2(g)]
ΔH0reaction = [-393.5 kj/mol] - [-110.5 kj/mol + 0]
ΔH0reaction = [-393.5 kj/mol] - [-110.5 kj/mol]
ΔH0reaction = -283 kj/mol
Always remember that a compound can be separated into simpler substances by chemical methods/reactions. While elements cannot be broken down into simpler substances by chemical reactions. You can do a flame test and spectrum analysis to determine whether a solid material is an element or a compound. Check the boiling and/or melting point, color or density. Also check the solid material’s reaction with oxygen, hydrogen, calcium, or various acids. Examine and study its physical chemistry. The element(s) that may be present may be identified by checking the absorption edges from an x-ray spectrum.
Answer:
The temperature of the gas.
Explanation:
According to the kinetic molecular theory, the molecules of a substance are in constant random motion.
If an ideal gas is contained is a sealed rigid container, the average velocity of the gas molecules is dependent of the temperature of the gas.
Recall that temperature is defined as the average kinetic energy of the molecules of a body.
