A. Quantity of saline = 500mL
Rate of infusion = 80 mL / h
Infusion time = Quantity / Rate = 500 mL / (80 mL/hr) = 6.25 hr
b. Child weight = 72.6 lb = 32.93 kg
Medrol to be given = 1.5 mg per kg
Quantity of Medrol = 20 mg/mL
Dosage available = 20 mg/mL / 1.5 mg/kg = 13.33 kg/mL
Dosage according to body weight = 32.93 kg / 13.33 kg/mL = 2.47 mL
Answer:
<em>3.27·10²³ atoms of O</em>
Explanation:
To figure out the amount of oxygen atoms in this sample, we must first evaluate the sample.
The chemical formula for sodium sulfate is <em>Na₂SO₄, </em>and its molar mass is approximately 142.05
.
We will use stoichiometry to convert from our mass of <em>Na₂SO₄ </em>to moles of <em>Na₂SO₄</em>, and then from moles of <em>Na₂SO₄ </em>to moles of <em>O </em>using the mole ratio; then finally, we will convert from moles of <em>O </em>to atoms of <em>O </em>using Avogadro's constant.
19.3g <em>Na₂SO₄</em> ·
·
·
After doing the math for this dimensional analysis, you should get a quantity of approximately <em>3.27·10²³ atoms of O</em>.
Answer:
The actual Van't Hoff factor for AlCl3 is 3.20
Explanation:
Step 1: Data given
Molarity of AlCl3 = 0.050 M
osmotic pressure = 3.85 atm
Temperature = 20 °C
Step 2: Calculate the Van't Hoff factor
AlCl3(aq) → Al^3+(aq) + 3Cl^-(aq)
The theoretical value is 4 ( because 1 Al^3+ ion + 3 Cl- ions) BUT due to the interionic atractions the actual value will be less
Osmotic pressure depends on the molar concentration of the solute but not on its identity., and is calculated by:
π = i.M.R.T
⇒ with π = the osmotic pressure = 3.85 atm
⇒ with i = the van't Hoff factor
⇒ with M = the molar concentration of the solution = 0.050 M
⇒ with R = the gas constant = 0.08206 L*atm/K*mol
⇒ with T = the temperature = 20 °C = 293.15 Kelvin
i = π /(M*R*T
)
i = (3.85) / (0.050*0.08206*293.15)
i = 3.20
The actual Van't Hoff factor is 3.20
Answer
D 160g
Explanation:
<u>Write the equation:</u>
Combustion reactions use oxygen and release water and heat, so
CH₃OH(g) + O₂(g) → CO₂(g) + H₂O(g)
Balance that:
2CH₃OH(g) + 3O₂(g) → 2CO₂(g) + 4H₂O(g)
<u>Find moles of carbon dioxide:</u>
We need to know the number of moles of CO₂. This rxn is at STP, so at STP one mole of gas = 22.4 liters.
112 L * 1 mol/22.4 L = <em>5 mol CO₂</em>
<u>Find moles of methanol:</u>
Based on the chemical equation, for every 2 mol methanol, there are 2 mol carbon dioxide. So for every 5 mol carbon dioxide, there are 5 mol methanol!
5 mol CO₂ = 5 mol CH₃OH
Molar mass of methanol: 12.01 + 3*1.008 + 16.00 + 1.008 = <em>32.04 g/mol</em>
Moles of methanol: 5 mol * 32.04 g/mol = 160.2 g methanol
≈ 160 mol methanol
A pure substance or a homogeneous mixture consists of a single phase. A heterogeneous mixture consists of two or more phases. When oil and water are combined, they do not mix evenly, but instead form two separate layers.