Answer:
A) Exothermic
B) (1) -410.5 kJ (2) -98.1 kcal
C) -976.44 kJ
Explanation:
A) By the value of ΔH (-1236 kJ), we can see that it's negative, it means that the heat is being lost by the reaction, and, because of that, the reaction is exothermic.
B) The molar mass of ethanol is 46.07 g/mol, so, at 15.3 grams, the number of moles is:
n = mass/molar mass
n = 15.3/46.07
n = 0.3321 mol
By the equation
1 mol of ethanol ----------------------- -1236 kJ
0.3321 mol of ethanol ----------------------- x
By a simple direct three rule:
x = -410.5 kJ
1 kJ --------------- 0.2390 kcal
-410 kJ ---------- y
y = -98.10 kcal
C) The molar mass of water is 18 g/mol, so the number of moles at 42.7 g is:
n = 42.7/18
n = 2.37 moles
By the equation
3 moles of water ----------------------- -1236 kJ
2.37 moles of water --------------------- x
By a simple direct three rule:
3x = -2929.32
x = -976.44 kJ
Answer:
heated test tube in cold water
B. Scientific claims can be verified through observation and experimentation, while pseudoscientific claims cannot. At least I think it is right.
A chemical property of a substance is a certain characteristic that can only be observed by participating in a chemical reaction. Alternatively, a chemical property of a substance is something that can only be observed when the substance undergoes a chemical change.
I'm not sure what you're supposed to do with the first four boxes; all four are examples of chemical properties. Do you have to name the specific type of chemical property as given in the description? If so, the following would be my answers:
Flammability/Combustibility: The ability of a substance to burn.
The next two are quite strange; I'm not aware of a term that cleanly describes reactivity with water or acid. I suspect that, given the level of the material here, the general property of "reactivity" might be the answer for both the second and third descriptions
(Water-)reactivity: Some substances react when put in water.
(Acid-)reactivity: Some substances react when put in acid.
Light sensitivity: Light can interact with some things to form new substances.
As for the chart, I've filled it in as shown in the attached image. Please take care to double-check what I've written; in particular, when it comes to the property, I might have used a different term from what you were taught in class or provided in some other resource that I don't have access to. I've also color-coded qualitative/quantitative and physical/chemical for your convenience.
Answer:
1 mole of a gas would occupy 22.4 Liters at 273 K and 1 atm
Explanation:
An ideal gas is a set of atoms or molecules that move freely without interactions. The pressure exerted by the gas is due to the collisions of the molecules with the walls of the container. The ideal gas behavior is at low pressures, that is, at the limit of zero density. At high pressures the molecules interact and intermolecular forces cause the gas to deviate from ideality.
An ideal gas is characterized by three state variables: absolute pressure (P), volume (V), and absolute temperature (T). The relationship between them constitutes the ideal gas law, an equation that relates the three variables if the amount of substance, number of moles n, remains constant and where R is the molar constant of the gases:
P * V = n * R * T
In this case:
- P= 1 atm
- V= 22.4 L
- n= ?
- R= 0.082

- T=273 K
Reemplacing:
1 atm* 22.4 L= n* 0.082
*273 K
Solving:

n= 1 mol
Another way to get the same result is by taking the STP conditions into account.
The STP conditions refer to the standard temperature and pressure. Pressure values at 1 atmosphere and temperature at 0 ° C (or 273 K) are used and are reference values for gases. And in these conditions 1 mole of any gas occupies an approximate volume of 22.4 liters.
<u><em>1 mole of a gas would occupy 22.4 Liters at 273 K and 1 atm</em></u>