8. A. Density is independent of size (an intensive property).
9. B. The highest density is 1786 g/20cm^3, or 89.3 g/cm^3. The least is 512 g/20cm^3, or 25.6 g/cm^3. Therefore, the difference is 89.3 - 25.6, or 63.7 g/cm^3.
10. C. A bottle filled with air weighs less than one filled with marshmallows, because air is less dense than marshmallows.
11. D. The number represents the number of protons in the nucleus of the atom, as well as the atomic number of the element.
12. C. The number represents the atomic mass of the element, which is determined based on the relative abundance of each form of the element.
Answer:
109.09°C
Explanation:
Given that:
the capacity of the cooling car system = 5.6 gal
volume of solute = volume of the water; since a 50/50 blend of engine coolant and water (by volume) is used.
∴ 
Afterwards, the mass of the solute and the mass of the water can be determined as shown below:
mass of solute = 
On the other hand; the mass of water = 
Molarity = 
= 
= 17.757 m
≅ 17.76 m
∴ the boiling point of the solution is calculated using the boiling‑point elevation constant for water and the Molarity.
where,
= 0.512 °C/m
= 100°C + 17.56 × 0.512
= 109.09 °C
Explanation:
is used for making ropes, used for climbing rocks and for making parachutes. Their usage shows that nylon fibres have high tensile strength
I believe it’s D because phosphorus has the mass of 30.9.
First we have to find moles of C:
Molar mass of CO2:
12*1+16*2 = 44g/mol
(18.8 g CO2) / (44.00964 g CO2/mol) x (1 mol C/ 1 mol CO2) =0.427 mol C
Molar mass of H2O:
2*1+16 = 18g/mol
As there is 2 moles of H in H2O,
So,
<span>(6.75 g H2O) / (18.01532 g H2O/mol) x (2 mol H / 1 mol H2O) = 0.74mol H </span>
<span>Divide both number of moles by the smaller number of moles: </span>
<span>As Smaaler no moles is 0.427:
So,
Dividing both number os moles by 0.427 :
(0.427 mol C) / 0.427 = 1.000 </span>
<span>(0.74 mol H) / 0.427 = 1.733 </span>
<span>To achieve integer coefficients, multiply by 2, then round to the nearest whole numbers to find the empirical formula:
C = 1 * 2 = 2
H = 1.733 * 2 =3.466
So , the empirical formula is C2H3</span>
