(2) silver (4) thallium
Answer: option (4) thallium.
Explanation:
1) You have to look at the normal boling and mleting points of the elements.
2) To be liquid the normal melting point must be lower than 758 K and the normal boiling point must be greater than 758 K.
3) The look at the data in a handbook of properties or in internet, and build a table.
4) The given temperature, 758K, is 758 - 273.15 = 484.85 °C.
Element Normal melting Normal boiling State at 484.85 °C
point (°C) point (°C)
(1) gold 1064 2700 solid
(2) silver 961.8 2162 solid(3) platinum 1768 3825 solid
(4) thallium 303.5 1457.8 liquidThen, the only element of the choices whose melting point is less than 758 K (484.85) and its boiling point is greater than that, at 1 atm is thallium. So, it is liquid.
The specific heat of the unknown sample has been .
Specific heat has been defined as the amount of heat required to raise the temperature of 1 gram of substance by 1 degree Celsius.
The specific heat (c) for a substance can be given by:
......(i)
Where, the heat required by the substance,
The mass of the substance has been,
The change in temperature of the system has been,
The change in temperature has been given as:
The initial temperature of the substance,
The final temperature of the substance,
Substituting the values for the change in temperature, :
Substituting the values in equation (i):
The specific heat of the unknown sample has been .
For more information about specific heat, refer to the link:
The correct answer is A. The temperature at which the motion of particles theoretically ceases.
Explanation:
The term "absolute zero" is used to refer to a temperature (degree of heat) in which particles have no movement or only minimal vibration as in this temperature the energy of particles is affected. Due to this, the absolute zero is one of the lowest temperatures that exists as it is equivalent to -273 °C or -459 °F, although it has been proved temperature can be even lower at certain circumstances. According to this, "absolute zero" is mainly defined by the lack of motion in particles and thus, the correct answer is "he temperature at which the motion of particles theoretically ceases".
Protists belong to the group eukaryotes (having their DNA enclosed inside the nucleus). They are not plants, animals or fungi but they act like one. They can be in general subgroups such as unicellular algae, protozoa and molds.
Answer: A - Structural models provide minimal three-dimensional information.
Explanation: