Answer: A thing that died a long time ago, and it's bones were preserved in the ground.
Explanation:
Because yes
Answer:
B
Explanation:
Behaviour therapy was popularized by the U.S. psychologist B.F. Skinner, who worked with mental patients in a Massachusetts state hospital.
Answer : The mass of 
needed are, 1.515 grams.
Explanation :
First we have to calculate the mole of 
.
Now we have to calculate the moles of .
The balanced chemical reaction will be,
![PbSO_4+Na_2CrO_4\rightarrow PbCrO_4+Na_2SO_4[tex]From the balanced chemical reaction, we conclude thatAs, 1 mole of [tex]PbCrO_4](https://tex.z-dn.net/?f=PbSO_4%2BNa_2CrO_4%5Crightarrow%20PbCrO_4%2BNa_2SO_4%5Btex%5D%3C%2Fp%3E%3Cp%3EFrom%20the%20balanced%20chemical%20reaction%2C%20we%20conclude%20that%3C%2Fp%3E%3Cp%3EAs%2C%201%20mole%20of%20%5Btex%5DPbCrO_4)
produced from 1 mole of
So, 0.005 mole of produced from 0.005 mole of
Now we have to calculate the mass of
Therefore, the mass of needed are, 1.515 grams.
Answer:
the answer is destructive interference
Answer:
2.04 x 10²⁴ molecules
Explanation:
Given parameters:
Mass of Be(OH)₂ = 145.5g
To calculate the number of molecules in this mass of Be(OH)₂ we follow the following steps:
>> Calculate the number of moles first using the formula below:
Number of moles = mass/molarmass
Since we have been given the mass, let us derive the molar mass of Be(OH)₂
Atomic mass of Be = 9g
O = 16g
H = 1g
Molar Mass = 9 + 2(16 + 1)
= 9 + 34
= 43g/mol
Number of moles = 145.5/43 = 3.38mol
>>> We know that a mole is the amount of substance that contains Avogadro’s number of particles. The particles can be atoms, molecules, particles etc. Therefore we use the expression below to determine the number of molecules in 3.38mol of Be(OH)₂:
Number of
molecules= number of moles x 6.02 x 10²³
Number of molecules= 3.38 x 6.02 x 10²³
= 20.37 x 10²³ molecules
= 2.04 x 10²⁴ molecules
