Answer:
The mass percent of gold in the rock is 2.500 %
Explanation:
Step 1: Data given
Mass of the rock = 12000 grams
Mass of gold = 300.0 grams
Step 2: Calculate mass %
Mass % = mass of gold / mass of gold
Mass % = (300.0 grams / 12000 grams) * 100 %
Mass % = 2.500 %
The mass percent of gold in the rock is 2.500 %
Solution:
1 moleof NaCl= 1 mole of Cl2 gas
0.178moles=xmole
now;0.178×1÷1=0.178moles
therefore chlorine will required 0.178 moles in order to produce sodium chloride.
<span>The total molecular dipole moment of a molecule is in general the vector sum of various local electric dipoles that exist in the molecule. These local electric dipoles are of two types that we will call bond dipoles and lone pair dipoles. A bond between two atoms, X and Y, in which the bond pair is unequally shared is called a polar bond.</span>
Methanol has the larger vapor pressure at room temperature because it has a lower molecular weight when compared with ethanol, which implies it has weaker intermolecular forces.
78.78 g out of 250 g of Thorium-234 would remain after 40 days.
Explanation:
All radioactive samples are unstable in nature and so they will be decaying with time. So the equation of disintegration of the radioactive element is given as
So N is the mass of the radioactive element at time t and is the mass of the radioactive element at initial stage. Here k is the disintegration constant and t is the time.
We can determine the disintegration constant from the half life term of any element.
So,
Since, the half life time of thorium-234 is known to be 24 days. Then, the disintegration constant is
As the given questions have the initial mass as 250 g and t is given as 40 days, then the mass after 40 days will be
Thus, 78.78 g of thorium-234 would remain after 40 days.