Answer:
I know that the 100-mL graduated cylinders are always read to 1 decimal place.
I think for 50 mL graduated cylinders, it lets you measure volumes up to 50.0 mL to the nearest 0.1 or 0.2 mL, depending on your exact cylinder.
Answer:
1. Exothermic.
2. -1598 kJ.
Explanation:
Hello!
1. In this case, according to the reaction, we can infer that 799 kJ of energy are evolved (given off, released) it means that the enthalpy of reaction is negative as the reactants have more energy than the products; which means this is an exothermic reaction.
2. Here, as we know that the enthalpy of reaction is -799 kJ/mol, we can compute the q-value as shown below, considering the reacted 2 moles of solid iron:

Which means that 1598 kJ of energy are evolved when 2 moles of solid iron react.
Best regards!
H2SO4 (1) H20 (g) + SO3 (g)
Answer:
A catalytic converter changes nitrogen dioxide to nitrogen gas and oxygen gas is a chemical change.
Explanation:
Hello.
In this case, since physical changes do not modify the molecular composition and structure of the material undergoing it whereas the chemical change does, for catalytic converters we should know they promote chemical reaction in which the composition is changed; for instance, for the given example, the following chemical reaction is the evidence:

As you can see, nitrogen and oxygen are no longer bonded but separated by themselves, therefore, this is a chemical change.
Best regards.
You didn’t show the cylinder containing water, so I created one that you can use as a model (see image).
The water level was originally at 37 mL.
Then you added the ball, and it displaced its volume of water.
The new volume reading is 52 mL, so
Volume of ball = volume of displaced water = 52 mL – 37 mL = 15 mL.