The answer is 7. Valence electrons are the electrons in the very last shell, so we need to look at the outer “circle” and count the electrons, or the little black dots. There are 7 in the last shell.
Answer: Volume of gas in the stomach, V = 0.0318L or 31.8mL
Explanation:
The number of moles of oxygen will remain constant even though the liquid oxygen will undergo a change of state to gaseous inside the person's stomach due to an increase in temperature.
<em>Number of moles of oxygen gas = mass/molar mass</em>
molar mass of oxygen gas = 32 g/mol
mass of oxygen gas = density * volume
mass of oxygen gas = 1.149 g/ml * 0.035 ml
mass of oxygen gas = 0.040215 g
Number of moles of oxygen gas = 0.0402 g/(32 g/mol)
Number of moles of oxygen gas = 0.00125 moles
<em>Using the ideal gas equation, PV=nRT</em>
where P = 1.0 atm, V = ?, n = 0.00125 moles, R = 0.082 L*atm/K*mol, T = (37 + 273)K = 310 K
<em>V = nRT/P</em>
V = (0.00125moles) * (0.082 L*atm/K*mol) * (310 K) / 1 atm
V = 0.0318L or 31.8mL
Answer:
157.79 g
Explanation:
The definition of molality is:
- molality = moles of solute / kilogram of solvent
This means that in a 2.7 molal solution, there are 2.7 moles of NaCl per kilogram of water.
So now w<u>e convert those 2.7 moles of NaCl to grams</u>, using its <em>molar mass</em>:
- 2.7 mol * 58.44 g/mol = 157.79 g
D. Electron cloud allowed the particles to pass through
Answer:
37.98 kPa.
Explanation:
- We can use the general law of ideal gas: PV = nRT.
where, P is the pressure of the gas in atm.
V is the volume of the gas in L.
n is the no. of moles of the gas in mol.
R is the general gas constant,
T is the temperature of the gas in K.
- If n and T are constant, and have different values of P and V:
<em>(P₁V₁) = (P₂V₂)</em>
<em></em>
P₁ = 101.3 kPa, V₁ = 1.5 L,
P₂ = ??? kPa, V₂ = 4.0 L.
- Applying in the above equation
<em>(P₁V₁) = (P₂V₂)</em>
<em></em>
<em>∴ P₂ = (P₁V₁)/V₂</em> = (101.3 kPa)(1.5 L)/(4.0 L) = <em>37.98 kPa.</em>
