Explanation:
when an iron bar rust is an example of a chemical change in which a new substance is formed and the change is not easily reversible.for iron to rust moisture and air must be present.while when a substance freezes,it can be easily reversed through melting and no new substance is formed.this change is termed a physical change.
Answer:
Metallic structure
Explanation:
They have a high melting point due to the strong forces of attraction between the positive ions (cations) and the delocalised electrons. Moreover, they conduct electricity due to the sea of delocalised electrons.
<em>[Extra: It could be an ionic compound since they also have a high melting point, however they only conduct electricity in liquid or aqeouus state.]</em>
The question is incomplete . The complete question is :
100 mg of an unknown protein are dissolved in enough solvent to make 5.00mL of solution. The osmotic pressure of this solution is measured to be 0.107atm at 25.0°C. Calculate the molar mass of the protein. Round your answer to 3 significant digits.
Answer: The molar mass of the protein is 
Explanation:


where,
= osmotic pressure of the solution = 0.107 atm
i = Van't hoff factor = 1 (for non-electrolytes)
Mass of solute (protein) = 100 mg = 0.1 g (Conversion factor: 1 g = 1000 mg)
Volume of solution = 5.00 mL
R = Gas constant = 
T = temperature of the solution = ![25^oC=[273+25]=298K](https://tex.z-dn.net/?f=25%5EoC%3D%5B273%2B25%5D%3D298K)
Putting values in above equation, we get:


Hence, the molar mass of the protein is 
The answer to this question is: B) 3+
The answer is Sliver reacts with nitric acid to produce a gas.