Answer:
2 significant figures i.e. 2 and 7.
Explanation:
We need to find the number of significant figures in the given number i.e. 
.
It has 2 significant figures i.e. 2 and 7.
It means the power of 10 doesn't count in the significant figures.
Hence, there are 2 significant figures.
<u>Answer:</u> The correct answer is Option B.
<u>Explanation:</u>
Molar mass is defined as the mass (in grams) of 1 mole of a substance. It is expressed in grams per mole.
Phosphorous is the 15th element in the periodic table, which belongs to Group 15 and Period 3. The molar mass of phosphorus element is 30.97 g/mol.
Hence, the correct answer is Option B.
Remember that the:
1. Vertical columns are groups and families
2. Horizontal columns are periods
3. Period 1 has 2 e-, 2 has 8 e-, 3 has 8 e-, and 4 has 18 e-
3.The number on top of the groups/families shows what group it is on (ex. 1A, 2A, 3B, 4B, etc) and the number on top of that indicates the number of the same thing (what group it is)
⇒ ex. 1A has 1 val e-. 2A has 2 val e-. 3A has 3 val e- ( and rest goes up until 8A). Note: I skipped the transitions metals since they don't have accurate amount of val e-.
4. Know which is the mass number, atomic number, symbol, or name.
5. Where the metals, non- metals, and metalloids are located.
6. Elements on the same groups have similar properties.
7. The first group is Akali Metals and are very unstable and very reactive
8. Second group is Akaline Earth Metals
9. The middle, groups 3-12 are Transition Metal
10. Group 13 is the Boron Family.
11. Group 14 is the Carbon Family
12. Group 15 is the Nitrogen Family
13. Group 16 is the Oxygen Family.
14. Group 17 is the Halogen, salt families
15. Group 18 is the Noble Gases, and are very stable and not reactive.
I hope this helps. :)
Answer:
1. Increasing the concentration of the acid
2. Increasing the temperature
Explanation:
CaCO₃ + 2HCl ⟶ CaCl₂ + H₂O + CO₂
Increasing the concentration of the acid increases the number of hydronium ions in contact with the surface of the CaCO₃ per unit time.
Increasing the temperature increases the kinetic energy of the hydronium ions, so they hit the surface of the CaCO₃ mor frequently and with greater force.
3. is wrong. The bigger the pieces, the smaller the surface area that is available for reaction.
