Answer:
D. has different properties when sampled in different areas.
Explanation:
The general property of a mixture says that each substance or component in a mixture has its individual or different property which can be separated on the basis of different methods.
Such as a mixture of oil and water is a heterogeneous mixture and have different properties or different densities, which helps them to be sampled in different areas.
Hence, the correct answer is "D".
Answer:
The group given the sugar pills.
Explanation:
The control group is the ones given sugar pills because they did not get the experimental aspirin
4. Molar mass of silver m Ms~=108 g/mol
Hence there are n=54*(1/108)=0.5 mols of Silver in 54 grams of Silver.
5. 6.3*(108/1)=680.4g
6. Avogadro's number : Na~=6.022×10^23<span>. </span>
6.0*(6.022*10^23/1)=36.132*10^23 atoms
7. Molar mass of Krypton : Mk=84 g/mol
112/84=1.33 moles of Kr
8. 1.93*10^24*(1/(6.022×10^23))=3.2 moles KF
9. Molar mass of Silicon : Ms=28 g/mol
86.2*(1/28)*(6.022×10^23/1)=18.5*10^23 atoms of silicon
10. Molar mass of Magnesium : M1=24 g/mol
4.8*10^24*(1/(6.022×10^23))*(24/1)=191 g Mg
False
Explanation: Carbon is the central atom which has valency of 4 and can form 4 bonds to complete its octet. Each chlorine has valency of 1 and can form only one bond to complete its octet. Thus carbon can bond with four chlorine atoms through sharing of electrons to form four single bonds. Thus it cannot contain a double bond.
<span>Answer: 100 ml
</span>
<span>Explanation:
1) Convert 1.38 g of Fe₂S₃ into number of moles, n
</span>i) Formula: n = mass in grass / molar mass
<span>
ii) molar mass of </span><span>Fe₂S₃ =2 x 55.8 g/mol + 3 x 32.1 g/mol = 207.9 g/mol
</span>
iii) n = 1.38 g / 207.9 g/mol = 0.00664 moles of <span>Fe₂S₃
</span>
<span>2) Use the percent yield to calculate the theoretical amount:
</span>
<span>65% = 0.65 = actual yield/ theoretical yield =>
</span>theoretical yield = actual yield / 0.65 = 0.00664 moles / 0.65 = 0.010 mol <span>Fe₂S₃</span><span>
3) Chemical equation:
</span>
<span> 3 Na₂S(aq) + 2 FeCl₃(aq) → Fe₂S₃(s) + 6 NaCl(aq)
4) Stoichiometrical mole ratios:
</span>
<span>3 mol Na₂S : 2 mol FeCl₃ : 1 mol Fe₂S₃ : 6 mol NaCl
5) Proportionality:
</span>2moles FeCl₃ / 1 mol Fe₂S₃ = x / 0.010 mol Fe₂S₃
<span>
=> x = 0.020 mol FeCl₃
6) convert 0.020 mol to volume
</span>
<span>i) Molarity formula: M = n / V
</span>
<span>ii) V = n / M = 0.020 mol / 0.2 M = 0.1 liter = 100 ml
</span>
