Answer:
3 bags are required.
Explanation:
Find the number of mg needed for 150 pounds
150 pounds * 5 mg/pound = 750 mg
1 bag = 250 mg
x bags = 750 mg Cross multiply
250 * x= 750 Divide by 250
x = 750/250
x = 3
The answer is 4.45 × 10²⁴ units.
To calculate this, we will use Avogadro's number which is the number of units (atoms, molecules) in 1 mole of substance:
6.02 × 10²³ units per 1 mole
So, we need a proportion:
If 6.02 × 10²³ units are in 1 mole, how many units will be in 7.40 moles:
6.02 × 10²³ units : 1 mole = x : 7.40 moles
After crossing the products:
1 mole * x = 7.40 moles * 6.02 × 10²³ units
x = 7.40 * 6.02 × 10²³ units
x = 44.5 × 10²³ units = 4.45× 10²⁴ unit
8 protons in oxygen bc it has an atomic number of 8
<h2>Answer:</h2>
There is only one valence electron in Al(OH)4- anion.
<h3>Explanation:</h3>
- Valency is the number of electrons in the outer most shell of an atom.
- In this compound, aluminium has the valency of +3. It means Al needs only 3 electrons to complete its outer most shell.
- Hence the stable molecule Al(OH)3.
- But the addition of one another OH- leads to the negative charge and there is one spare electron which can make bond to an atom to stable the compound.
Answer:
The true statement about the discovery of electrons is :
C. Electrons were discovered in a vacuum tube
Explanation:
In 1870, Sir William Crookes developed the first cathode ray tube which have high vacuum inside.
These rays moved the paddled wheel when placed in their path.This means these rays have some momentum.
When the magnetic field was applied to the cathode rays they showed deflection. This means these cathode rays must have some charge because only charged particles can show deflection when place in magnetic field.
Later is was found by J.J Thomson that these are negatively charged.
How ?
We Know that like charges repel each other and unlike charges attract each other. This means if a particle has negative charge then it will attract the positive charge.
J.J Thomson studied these cathode ray tubes and found that these rays repels the negative charge particles .Hence these rays must be negatively charged.
He called these tiny Particle "electron"