Answer:
The blood circulatory system (cardiovascular system) delivers nutrients and oxygen to all cells in the body. It consists of the heart and the blood vessels running through the entire body. The arteries carry blood away from the heart; the veins carry it back to the heart.
Explanation:
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<span>The molecular mass of sodium oxide (Na2O) is A. 61.97894. The molecular mass of a molecule (Mr) is the sum of atomic masses of its atoms (Ar). The molecular mass of sodium oxide is: Mr(Na2O) = 2 * Ar (Na) + Ar(O). From the periodic table, Ar(Na) = 22.989769 and Ar(O) = 15.9994. The molecular mass of sodium oxide is: Mr(Na2O) = 2 * 22.989769 + 15.9994 = 45.979538 + 15.9994 = 61.97894.</span>
Answer:
Explanation:
Data:
H₃O⁺ + OH⁻ ⟶ 2H₂O
V/mL: 50.0 50.0
c/mol·L⁻¹: 1.0 1.0
ΔT = 6.5 °C
ρ = 1.210 g/mL
C = 4.18 J·°C⁻¹g⁻¹
C_cal = 12.0 J·°C⁻¹
Calculations:
(a) Moles of acid

(b) Volume of solution
V = 50.0 mL + 50.0 mL = 100.0 mL
(c) Mass of solution

(d) Calorimetry
There are three energy flows in this reaction.
q₁ = heat from reaction
q₂ = heat to warm the water
q₃ = heat to warm the calorimeter
q₁ + q₂ + q₃ = 0
nΔH + mCΔT + C_calΔT = 0
0.0500ΔH + 1.10×4.18×6.5 + 12.0×6.5 = 0
0.0500ΔH + 2989 + 78.0 = 0
0.0500ΔH + 3067 = 0
0.0500ΔH = -3067
ΔH = -3067/0.0500
= -61 000 J/mol
= -61 kJ/mol

Note: The answer can have only two significant figures because that is all you gave for the change in temperature.