Answer:
Half life = 79.67 sec
Explanation:
Given that:
k = 
The expression for half life is shown below as:-
Where, k is rate constant
So,
Half life = 79.67 sec
Answer:
1.97 moles of Na contains greater number of atoms than 6.8 × 10²² atoms of Li.
Explanation:
To solve this problem we will first calculate the number of atoms contained by 1.97 moles of Na and then will compare it with 6.8 × 10²² atoms of Li.
As we know that 1 mole of any substance contains exactly 6.022 × 10²³ particles which is also called as Avogadro's Number. So in order to calculate the number of atoms contained by 1.97 moles of Na, we will use following relation,
Moles = Number of Atoms ÷ 6.022 × 10²³ atoms.mol⁻¹
Solving for Number of Atoms,
Number of Atoms = Moles × 6.022 × 10²³ Atoms.mol⁻¹
Putting values,
Number of Atoms = 1.07 mol × 6.022 × 10²³ Atoms.mol⁻¹
Number of Atoms = 1.18 × 10²⁴ Atoms of Na
Hence,
1.97 moles of Na contains greater number of atoms than 6.8 × 10²² atoms of Li.
Answer:
Chemical Change
Explanation:
chemical bonds within the substance have been altered because a new substance has been produced. It cannot be a mixture because they do not involve changes in matter, it cannot be a physical change because they do not result in new substances, it is not a solution because those do not involve changes in matter.
The element first discovered in the sun is the element Helium. This noble gas is the second most abundant element<span> in the universe and was </span>discovered<span> on the </span>sun<span> before it was discovered on the earth. Helium is the result of the nuclear fusion of hydrogen creating thus the mass of energy in the sun.</span>
Answer:
In physics and chemistry, the law of conservation of mass or principle of mass conservation states that for any system closed to all transfers of matter and energy, the mass of the system must remain constant over time, as the system's mass cannot change, so quantity can neither be added nor be removed.
Explanation:
That is what I think on the subject
