Answer: HCl
Explanation:
calcium carbonate dissolves in HCl acid producing CO 2 gas. It will not dissolve in pure water. The Ksp for calcium carbonate in water is 3.4 x 10-9 moldm-3 which is very low. What takes place here is actually a chemical reaction:
CaCO 3 (s) + 2HCl(aq) → CaCl 2 (aq) + H 2CO 3(aq)
This reaction accounts for the solubility of the Calcium carbonate in HCl and not in pure water.
Answer : The molecule
is a polar molecule.
Explanation :
Polar molecule : When the arrangement of the molecule is asymmetrical then the molecule is polar.
Non-polar molecule : When the arrangement of the molecule is symmetrical then the molecule is non-polar.
The given molecule is, 
The electronegativities of oxygen and fluorine are different. The molecular geometry of
is bent. As, Fluorine is more elctronegative than the oxygen. So, the arrows putting towards the more electronegative element i.e, fluorine. These arrows do not balance each other. Due to this, the asymmetrical arrangement of these bonds makes the molecule polar.
Hence, the given molecule
is polar.
<u>Answer:</u> The molecular weight of protein is 
<u>Explanation:</u>
To calculate the concentration of solute, we use the equation for osmotic pressure, which is:

or,

where,
= Osmotic pressure of the solution = 0.0861 atm
i = Van't hoff factor = 1 (for non-electrolytes)
= mass of protein = 400 mg = 0.4 g (Conversion factor: 1 g = 1000 mg)
= molar mass of protein = ?
= Volume of solution = 5.00 mL
R = Gas constant = 
T = temperature of the solution = ![25^oC=[25+273]K=298K](https://tex.z-dn.net/?f=25%5EoC%3D%5B25%2B273%5DK%3D298K)
Putting values in above equation, we get:

Hence, the molecular weight of protein is 
A heterogeneous mixture is a mixture that it's components can be easily seen and separated.
c. a jar of mixed nuts
Answer:
Gravitational potential energy may be converted to other forms of energy, such as kinetic energy. If we release the mass, gravitational force will do an amount of work equal to mgh on it, thereby increasing its kinetic energy by that same amount (by the work-energy theorem).
Explanation: