Answer:
Semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.
Explanation:
A semiconductor can be defined as a crystalline solid substance that has its conductivity lying between that of a metal and an insulator, due to the effects of temperature or an addition of an impurity. Semiconductors are classified into two main categories;
1. Extrinsic semiconductor.
2. Intrinsic semiconductor.
The statement which best describes the electrical conductivity of metals and semiconductors is that semiconductors are poor conductors at low temperatures, but their resistance decreases with increasing temperature.
This ultimately implies that, semiconductors are typically an insulator (poor conductor) at low temperatures and a good conductor at high temperatures.
Additionally, conduction involves the transfer of electric charge or thermal energy due to the movement of particles. When the conduction relates to electric charge, it is known as electrical conduction while when it relates to thermal energy, it is known as heat conduction.
The molarity of a solution equals to the mole number of the solute/the volume of the solution. For NH4Br, we know that the mole mass is 98. So the molarity is (14/98) mol /0.15 L=0.95 mol/L.
Non-polar covalent
Explanation:
Propane is made up of non-polar covalent bonds and it can be expected to dissolve in hexane and to not dissolve in water.
Propane is an hydrocarbon gas.
It forms by sharing of electrons between two atoms with very low electronegativity differences.
This differences results in equal sharing of the shared electron. Therefore they form a non-polar covalent bond.
Water is a polar covalent compound and cannot dissolve compounds that are not polar like propane.
Propane will only dissolve in a like substance like hexane which is equally non-polar.
learn more:
Covalent compounds brainly.com/question/3109255
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2 Corsls provide treatments
I can't actually answer this one if the empirical formula is not given. Luckily, I've found a similar problem from another website. The problem is shown in the picture attached. It shows that the empirical formula is CH₂O. Let's calculate the molar mass of the empirical formula.
Molar mass of E.F = 12 + 2(1) + 16 = 30 g/mol
Then, let's divide this to the molar mass of the molecular formula.
Molar mass of M.F/Molar mass of E.F = 180/30 = 6
Therefore, let's multiply 6 to each subscript in the empirical formula to determine the actual molecular formula.
<em>Actual molecular formula = C₆H₁₂O₆</em>
