Answer: 1. Block
2. True ( I'm unsure. He arranged it according to mass, but he is credited for the periodic table)
3. Noble gasses
4. technetium
5. Alkaline earth metals
6. Number of protons
7. False
8. Not true: generally decreases as atomic number increases within a period
9. Argon
10. Four
11. False
12. False
Explanation:
Heat. When heat is appplied to liquid it turns into gas.
Answer:
Explanation:
H3PO4(aq) + 3NaOH(aq) → Na3PO4(aq) + 3H2O(l)
mole of NaOH = 23.6 * 10 ⁻³L * 0.2M
= 0.00472mole
let x be the no of mole of H3PO4 required of 0.00472mole of NaOH
3 mole of NaOH required ------- 1 mole of H3PO4
0.00472mole of NaOH ----------x
cross multiply
3x = 0.0472
x = 0.00157mole
[H3PO4] = mole of H3PO4 / Vol. of H3PO4
= 0.00157mole / (10*10⁻³l)
= 0.157M
<h3>The concentration of unknown phosphoric acid is 0.157M</h3>
