Answer:
3.861x10⁻⁹ mol Pb⁺²
Explanation:
We can <u>define ppm as mg of Pb²⁺ per liter of water</u>.
We<u> calculate the mass of lead ion in 100 mL of water</u>:
- 100.0 mL ⇒ 100.0 / 1000 = 0.100 L
- 0.100 L * 0.0080 ppm = 8x10⁻⁴ mg Pb⁺²
Now we <u>convert mass of lead to moles</u>, using its molar mass:
- 8x10⁻⁴ mg ⇒ 8x10⁻⁴ / 1000 = 8x10⁻⁷ g
- 8x10⁻⁷ g Pb²⁺ ÷ 207.2 g/mol = 3.861x10⁻⁹ mol Pb⁺²
Answer : The concentration of Si in kilograms is, 
Explanation :
As we are given that, the concentration of Si in an Fe-Si alloy is 0.25 wt% that means:
Weight of Si = 0.25 g = 0.00025 kg
Weight of Fe = 100 - 0.25 = 99.75 g = 0.09975 kg
Density of Si = 
Density of Fe = 
Now we have to calculate the concentration in kilograms of Si per cubic meter of alloy.
Concentration of Si in kilograms = 
Concentration of Si in kilograms = 
Now put all the given values in this expression, we get:
Concentration of Si in kilograms = 
Concentration of Si in kilograms =
Thus, the concentration of Si in kilograms is,
Answer:
The force increases because it is part of a Newton’s third law pair of forces with the force that the star exerts on the planet.
Explanation:
Force between two objects can be expressed by an equation:
F = G • m1 • m2 / r^2,
where m1 and m2 are objects' masses, r is the distance between them, and G is a gravitational constant.
That means that greater the masses or lesser the distance, the force will be greater, and vice versa.
This force exists between any two objects, but is generally extremely weak, so it's best observed with big and large objects with great mass, such as planets and stars.
This force, whatever its magnitude may be, always works on both objects, following the third Newton's law.
So, whatever the force the stat exerts on the planet is, the planet will exert the same amount of force on the star.
Answer:
relative rate of diffusion is 1.05
Explanation:
According to Graham's law of difussion:
Rate of diffusion is inversely proportional to the square root of molecular weight of a molecule.
For two given molecules:
The given molecules are
Water = 18.01
Heavy water =20.03
Thus the relative rate of diffusion will be:
Answer:
d.) Microwave photons cause the molecules to increase their rotational energy states, whereas infrared photons cause electrons in the molecules to increase their electronic energy states.
Explanation:
Microwave: transitions in the molecular rotational levels
Infrared: transitions in molecular vibrational levels
UV/Visible: transitions in electronic energy levels.
