Answer:
A and B
Explanation:
the other two make no sense at all
Answer:
1) chemical indicators won't work above it's pH range so therefore it probably won't change colour.
2) the solution should be clear and colourless to see colour change.
3) indicators tend to be of low accuracy so it's not 100% reliable.
Answer:
I think that gravity can be considered a force.
Explanation:
As the object falls, it moves faster and faster. Gravity is considered a universal force because it acts between any two masses anywhere in the universe. For example, there is a gravitational pull between the Sun and the Moon. Even small masses attract one another.
Hope this helped! :)
Answer:
T2 = 94.6 C
Explanation:
Use Clausius-Clayperyon equation.
ln P1/P2 = ∆Hvap/R (1/T2 - 1/T1) where R = 8.314 J/mol-K and T is in degrees K
P1 = 760 mmHg
P2 = 630 mmHg
T1 = 373 K
T2 = ?
∆Hvap = 40.7 kJ/mole
R = 0.008314 kJ/mole-K (NOTE: change R to units of kJ)
Plug in and solve for T2
ln 760 mmHg/630 mmHg = 40.7 kJ/mole (1/T2 - 1/373K)
T2 = 367.74 K = 94.6 C
When a substance is undergoing a change of state, the heat that is been added to the substance at that particular point in time is used to work on the chemical bonds that is holding the molecules of the substance together; the heat is not used to increase the temperature of the substance at that particular point. For instance, in the case of ice, at its melting point the heat supplied is used to break the inter molecular force that is holding the particles of the ice together. When the bonds are completely broken and the ice has to liquid then the temperature of the water will increase.
