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.
Answer:
Solid, Liquid, Gas and, Plasma
Explanation:
A solid has a definite shape and volume. A liquid has a definite volume but takes the shape of its container. A gas lacks either a defined shape or volume. Plasma is similar to a gas in that its particles are very far apart, but gas is electrically neutral and plasma has a charge.
Answer:
Option d.
1 mole AlCl3in 500 g water
Explanation:
ΔT = Kf . m . i
Freezing T° of solution = - (Kf . m . i)
In order to have the lowest freezing T° of solution, we need to know which solution has the highest value for the product (Kf . m . i)
Kf is a constant, so stays the same and m stays also the same because we have the same moles, in the same amount of solvent. In conclussion, same molality to all.
i defines everything. The i refers to the Van't Hoff factor which are the number of ions dissolved in solution. We assume 100 & of ionization so:
a. Glucose → i = 1
Glucose is non electrolytic, no ions formed
b. MgF₂ → Mg²⁺ + 2F⁻
i = 3. 1 mol of magnessium cation and 2 fluorides.
c. KBr → K⁺ + Br⁻
i = 2. 1 mol potassium cation and 1 mol of bromide anion
d. AlCl₃ → Al³⁺ + 3Cl⁻
i = 4. 1 mol of aluminum cation and 3 mol of chlorides.
Kf . m . 4 → option d will has the highest product, therefore will be the lowest freezing point.
The correct option is B.
Carbon is an element with an atomic number of 6. Each atom of carbon is made up of electron, proton and neutron. Carbon has six protons and six neutrons in its atom but its number of neutrons differ. This is because carbon exhibit isotopy. The isotopes of carbon are: carbon 12, carbon 13 and carbon 14. Carbon 12 has 6 neutrons, carbon 13 has 7 neutrons and carbon 14 has 8 neutrons.
Your answer is: A. tetrahedral
Hope this helped! :D
