Answer:
1.48 x 10^47 mol of Na
Explanation:
8.90 x 10^24 atoms of Na (1 mol of Na/6.022 x 10^23 atoms of Na)=
1.48 x 10^47 mol of Na
Answer : As the temperature of a medium increases, the speed of the sound wave increases because the particles bump into each other more often.
Explanation :
The dependency of the speed of the sound wave and the temperature of the medium is :
Where
= ratio of specific heat
R is gas constant
T is the temperature
The speed of the wave is directly proportional to the temperature. As the temperature of a medium increase, the speed of the sound increase. The particles start vibrating faster. Hence, they bump into each other.
Hence, the correct option is (A).
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:
An example of a chemical property of iron would be that it is capable of combining with oxygen to form iron oxide, or rust.
Explanation:
You have no choice listed, so I provided an example.
Answer:
B. NaBr
D. KOH
Explanation:
Below is the solubility rules given for you knowledge.
Salts of
- Group 1 elements are soluble(
) - Ammonium ion is soluble (
) - The nitrate are generally soluble(
- of Cl- , Br- , and I- are soluble, except Ag+ , Pb+2, and (Hg2)+2
- most sulfate are soluble, except Ba+2, Ca+2,Pb+2, Ag+, Sr+2.
- most hydroxide salts are only slightly soluble, except NH+4, Li+, Na+, K+
- Most carbonates are insoluble (CO3 2-) Except group 1 and NH+4
- most phosphate are insoluble except group 1 and NH+4
so using the rules above
NaBr , KOH are soluble, Pb(OH)2 is slightly soluble and AgCl is not soluble.
