Answer:
A. A line graph
Explanation:
You use line graphs to track changes over time. Line graphs are better when the changes are small. They are also more useful when you want to compare changes over the same period for more than one group, for example, plants exposed to music and a control group.
B is wrong. A pie chart is best for comparing parts of a whole.
C is wrong. You can use a bar graph to track changes over time, but small changes are harder to spot.
D is wrong. You use a timeline to mark important points in time, for example, when you are deciding the times when you must complete various stages of a project.
Which of the charts below do you think is more helpful in showing the change in plant height over time?
Sulfur has the same amount, like all the other elements in group 16, has six valence electrons.
Answer:
Explanation:
The total energy or intrinsic energy of a system is called the enthalpy. In thermochemistry, we have two types of enthalpy changes which are:
- Exothermic changes
- Endothermic changes
For the freezing of water, the enthalpy change is an exothermic one. Exothermic changes are designated as negative. In this chemical change, heat is liberated to the surroundings and this leaves the environment at a much higher temperature. In freezing, the enviroment gains more heat as the material begins to cool to lower temperature.
Entropy is the degree of randomness or disorderliness of a system. When a phase change occurs from liquid to solid, freezing takes place. Such a change increases the orderliness of a system and entropy diminishes. Here, entropy is negative.
The free energy is a measure of the energy a system that does useful work. Free energy depends on enthalpy, entropy and temperature of a system. For phase changes such as freezing of water, the value of free energy change is 0.
For this process, an increases in temperature makes it non-spontaneous. Increasing temperature would alter the course of the reaction and makes it exothermic. For entropy, increasing temperature would increase entropy and therefore, the reaction would not be feasible.
Temperature would mostly affect the free energy. An increase in temperature would increase the value of entropy change and the reaction would not be spontaneous. With falling temperature value, the reaction becomes more spontaneous and favored.
1 mole of nacl has 1 mole of na ions
therefore 2 moles of nacl has 2 moles of na ions
Mole x L
= 2x6.02x10^23
=12.04 x 10^23
