Answer:
0.012× 10⁻²³ moles of iron
Explanation:
Given data:
Number of moles of iron = ?
Number of iron atoms = 0.0723 atom
Solution:
Avogadro number:
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance. The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ atoms
0.0723 atom × 1 mol / 6.022 × 10²³ atoms
0.012× 10⁻²³ mol
Answer:
The first equation
Explanation:
For these problems, it is best to label and record how many of each element are on each side of the equation. The first equation has 1 Ca, 2H, and 2Cl on both sides while the second equation has 3H on the left and 2H on the right making the second equation incorrect.
Answer:
increasing its temperature
using a longer wire
using a thinner wire
Answer:
1. Dissolving powder in milk - Chemical
- It is chemical because the milk has changed on a molecular level
2. Toasting bread - Chemical
- It is chemical because adding heat to the bread cooks it, therefore
changing it on a molecular level
3. Melting cheese - Physical
- It is physical because the physical appearance was the only change
4. Slicing apples or bannanas - Physical
- It is physical because the physical appearance was the only change
5. Frying an egg - Chemical
- It is chemical because new particles were formed
6. Milk souring - Chemical
- It is chemical because it is forming a new product (lactic acid)
Explanation:
Physical Change occurs when the particles of a substance become rearranged, but do not change into different particles.
Chemical change occurs when a new substance is formed. This process is irreversable.
atomic number is equal to proton number
so the proton number will be 87
