<span>Answer:
For this problem, you would need to know the specific heat of water, that is, the amount of energy required to raise the temperature of 1 g of water by 1 degree C. The formula is q = c X m X delta T, where q is the specific heat of water, m is the mass and delta T is the change in temperature. If we look up the specific heat of water, we find it is 4.184 J/(g X degree C). The temperature of the water went up 20 degrees.
4.184 x 713 x 20.0 = 59700 J to 3 significant digits, or 59.7 kJ.
Now, that is the energy to form B2O3 from 1 gram of boron. If we want kJ/mole, we need to do a little more work.
To find the number of moles of Boron contained in 1 gram, we need to know the gram atomic mass of Boron, which is 10.811. Dividing 1 gram of boron by 10.811 gives us .0925 moles of boron. Since it takes 2 moles of boron to make 1 mole B2O3, we would divide the number of moles of boron by two to get the number of moles of B2O3.
.0925/2 = .0462 moles...so you would divide the energy in KJ by the number of moles to get KJ/mole. 59.7/.0462 = 1290 KJ/mole.</span>
Answer:
I think the answer is D.
Explanation:
Because if it is unsaturated then it can dissolve more solutes.
Answer:
Kb = [OH⁻] . [C₃H₉NH⁺] / [ C₃H₉N ]
Explanation:
The equation for the reaction of trimethylamine when it is dissolved in water is:
C₃H₉N + H₂O ⇄ C₃H₉NH⁺ + OH⁻ Kb
1 mol of trimethylamine catches a proton from the water in order to produce trimethylamonium.
It is a base, because it give OH⁻ to the medium
Expression for Kb (Molar concentration)
Kb = [OH⁻] . [C₃H₉NH⁺] / [ C₃H₉N ]
Answer:
Federal, State, Municipal and County
Explanation:
A decentralized system of crime laboratories currently exists in the United States under the auspices of various governmental agencies at the federal, state, municipal and county levels of government.
Answer:
Molarity is halved when the volume of solvent is doubled.
Explanation:
Using the dilution equation (volume 1)(molarity 1)=(volume 2)(molarity 2), we can demonstrate the effects of doubling volume.
Suppose the starting volume is 1 L and the starting molarity is 1 M, and doubling the volume would make the final volume 2 L.
Plugging these numbers into the equation, we can figure out the final molarity.
(1 L)(1 M)=(2 L)(X M)
X M= (1 L x 1 M)/(2 L)
X M= 1/2 M
This shows that the molarity is halved when the volume of solvent is doubled.
