Answer:
Option (B) is correct.
Explanation:
Given that the molecules of hydrogen gas (
) react with molecules of oxygen gas (
) in a sealed reaction chamber to produce water (
).
The governing equation for the reaction is
From the given, the only fact that can be observed that 2 moles of and 1 mole of reacts to produce 2 moles of .
As the mass of 1 mole of 
grams ... (i)
The mass of 1 mole of 
grams ...(ii)
The mass of 1 mole of 
grams (iii)
Now, the mass of the reactant = Mass of 2 moles of + mass 1 mole of
[ using equations (i) and (ii)]
grams.
Mass of the product = Mass of 2 moles of
[ using equations (iii)]
=36 grams
As the mass of reactants = mass of the product.
So, mass is conserved.
Hence, option (B) is correct.
An object that's moving doesn't necessarily change its speed or acceleration. Also, the force applied to it doesn't need to change ... in fact, a moving object doesn't need ANY force applied to it in order to keep moving.
But any moving object WILL have a change in its position ... THAT's how you know it's moving, and that's WHY you say "It's moving !". (choice-B)
Answer : When a person applies force and covers distance then the person is doing work on an object.
Answer:
A compass works by detecting and responding to the Earth's natural magnetic fields. The Earth has an iron core that is part liquid and part solid crystal, due to gravitational pressure. It is believed that movement in the liquid outer core is what produces the Earth's magnetic field.
Explanation:
Answer:
a. Approximate umber of atoms = 10¹¹
b. number of atoms = 50 atoms thick
Note: The question is missing some parts. The complete question is as follows; Calculate the approximate number of atoms in a bacterium. Assume that the average mass of an atom in the bacterium is ten times the mass of a hydrogen atom. (Hint: The mass of a hydrogen atom is on the order of 1×10⁻²⁷ kg and the mass of a bacterium is on the order of 1×10⁻¹⁵ kg)
Explanation:
a. Approximate umber of atoms = mass of bacterium / 10 * mass of hydrogen
number of atoms = 10⁻⁵/ 10 × 10⁻²⁷
number of atoms = 10¹¹ atoms
b. The cell membrane is 10-8 m thick while the hydrogen atom has a diameter of 10-10 m.
The number of atoms in the cell membrane = d1 / 2 × d2
where d1 = diameter of cell membrane; d2 = diameter of hydrogen atom
The number of atoms in the cell membrane = 10⁻ / 2 × 10⁻¹⁰ = 50 atoms
