The question incomplete , the complete question is:
A student dissolves of 18.0 g urea in 200.0 mL of a solvent with a density of 0.95 g/mL . The student notices that the volume of the solvent does not change when the urea dissolves in it. Calculate the molarity and molality of the student's solution. Round both of your answers to significant digits.
Answer:
The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.
Explanation:
Moles of urea = 
Volume of the solution = 200.0 mL = 0.2 L (1 mL = 0.001 L)
Molarity of the urea solution ;
Mass of solvent = m
Volume of solvent = V = 200.0 mL
Density of the urea = d = 0.95 g/mL
(1 g = 0.001 kg)
Molality of the urea solution ;
The molarity and molality of the student's solution is 1.50 Molar and 1.58 molal.
Answer:
a. BH₃
Explanation:
According to the octet rules, atoms reach stability when are surrounded by eight electrons in their valence shell when they combine to form a chemical compound.
From the options, the only compound in which the central atom does not meet the octet rules is BH₃. The central atom is boron (B), which has 3 electrons in its valence shell. When B is combined with hydrogen (H), 3 electrons from the 3 atoms of H are added. The total amount of electrons is 6, fewer than 8 electrons needed to meet the rule.
hope this helps
Co2
Explanation:
CH4 (g) + 2 O2 (g) → CO2 (g) + 2 H2O (l)
Answer:
Salinity, along with temperature, determines the density of seawater, and hence its vertical flow patterns in thermohaline circulation. 2. Salinity records the physical processes affecting a water mass when it was last at the surface. Hope this helps!
Explanation:
We’ll be using the equation:
dG = dH - TdS (replace ‘d’ with triangle)
I’m going to assume 0 degrees Celsius.
At 0 C (273 K):
dG = dH - TdS
dG = (285,400 J) - (273 K)(-137.14 J/K)
dG = 285,400 J + 37,439.2 J
dG = 322,839.2 J or 322.84 kJ
The dG of this reaction is +322.84 kJ. This reaction is not considered spontaneous.
This answer, in this instance, would be D. If the temperature used in the question is not 0 degrees C, replace the temperature that I used for calculation with the Kelvin temperature given in the problem (K = C + 273), and simplify to find the answer.
