Answer: Protons have a positive charge. Electrons have a negative charge. The charge on the proton and electron are exactly the same size but opposite. Neutrons have no charge.
Explanation:
Answer: 5.5
Explanation: Strontium titanate is both much denser (specific gravity 4.88 for natural, 5.13 for synthetic) and much softer (Mohs hardness 5.5 for synthetic, 6–6.5 for natural) than diamond.
Answer:
pH = 4.34
Explanation:
pH= -1/2(logKa) -1/2(log C)
= -1/2( log 5.98*10^-8) -1/2(log 0.0353)
=-1/2(-7.22)-1/2(-1.45)
=3.61+0.725= 4.34
<h3>
Answer:</h3>
Single displacement reaction
<h3>
Explanation:</h3>
- Single replacement reaction is a type of reaction in which a reactive element displaces a less reactive element from its compound.
- The reaction given above; Al + H₂SO₄ → Al₂(SO₄)₃ + H₂ is a single replacement reaction.
- This is because Aluminium takes the place of hydrogen atoms in sulfuric acid to form aluminium sulfate and hydrogen gas.
- Double replacement reaction is where cations or anions are exchanged between two compounds to form new compounds.
- For example the reaction; NaCl(aq) + AgNO₃(aq) → NaNO₃(aq) + AgCl(aq) is a double displacement reaction.
Answer:
2. All the naturally occurring isotopes of Mg.
Explanation:
You want to know the atomic mass of the magnesium you use in the lab. That’s “natural” magnesium. So, you must use the weighted average of all the naturally occurring isotopes in natural Mg.
1. and 3. are <em>wrong</em>. You won’t get the correct mass for natural Mg if you use only the artificial isotopes for your calculation.
4. is <em>wrong</em>. You must use all the naturally occurring isotopes. The two most abundant isotopes of Mg account for only 90 % of the atoms. If you ignore the other 10 %, your calculation will be wrong.
