Answer:
w = -531 kJ
1. Work was done by the system.
Explanation:
Step 1: Given data
- Heat gained by the system (q): 687 kJ (By convention, when the system absorbs heat, q > 0).
- Change in the internal energy of the system (ΔU°): 156 kJ
Step 2: Calculate the work done (w)
We will use the following expression.
ΔU° = q + w
w = ΔU° - q
w = 156 kJ - 687 kJ
w = -531 kJ
By convention, when w < 0, work is done by the system on the surroundings.
Answer: An atom with 6 protons, 5 electrons, and 7 neutrons
Explanation: In this case, neutrons do not matter as they have a charge of 0, or no charge. A proton has a charge of +1 and an electron has a charge of -1. Since there are 6 protons, the total charge of the protons would be +6. Since there are 5 electrons the total charge of the electrons would be -5. +6 - 5 would result in a charge of +1. This means that this atom would have an overall charge of + 1. Basically, if there is one more proton than electron, then the overall charge of the atom will be +1 but if there is one more electron than proton, then the overall charge of the atom will be -1.
Answer:
D.phototropism
Explanation:
Phototropism is a type of tropism in which a plant or plant part responds to light. According to this question, a student wanted to investigate the effect of light on the growth of cress seedlings. The student used three different pots for the experiment.
Pot 1 was placed with light from above. Pot 2 was placed in a cupboard with no light. Pot 3 was placed in a window with light from one direction only. However, the image attached to this question shows that the plants in the different pots face different directions in response to light, which depicts phototropism
Answer:
<span>Formula New Combination Predicted Formula
</span>
NaCl potassium + chlorine KCl
AlCl₃ aluminum + fluorine AlF₃
CO₂ tin + oxygen SnO₂
MgCl₂ calcium + bromine CaBr₂
HCl cesium + iodine CsI
<span>
CCl₄ silicon + bromine SiBr₄</span>
Explanation:
1) The question is incomplete. The first part is missing.
This is the first part of the question.
<span>Applying
the principle that the elements of a particular column in the Periodic
Table share the same chemical properties, complete the following chart.
The first one has been done for you.
</span>
2) This is the given chart:
<span>Formula New Combination Predicted Formula
</span>
Cu₂O silver + oxygen Ag₂O ← this is the example.
NaCl potassium + chlorine
<span>
AlCl₃ aluminum + fluorine </span>
CO₂ tin + oxygen
<span>
MgCl₂ calcium + bromine </span>
<span>
HCl cesium + iodine </span>
<span>
CCl₄ silicon + bromine
</span>
3) This is how you find the new formula to complete the chart.
i) NaCl potassium + chlorine
Since potassium is in the same group of sodium, you predict that in the new formula Na is replaced by K giving KCl.
ii) AlCl₃ aluminum + fluorine
Since fluorine is in the same group that Al, then you predict that in the new formula Cl is replaced by F leading to AlF₃
iii) CO₂ tin + oxygen
Since tin is in the same group that C, you predict that in the new formula C is replaced by Sn leading to SnO₂
iv) MgCl₂ calcium + bromine
Since calcium is in the same group that Mg, and bromine is in the same group that Cl, you predict thea in the new formula calcium replaces Mg and bromine replaces Cl, leading to CaBr₂
v) HCl cesium + iodine
Since H is in the same column that cesium and Cl is in the same colum that iodine, you predict that in the new formula Cs replaces H and I replaces Cl leading to: CsI
<span>
vi) CCl₄ silicon + bromine
</span>
Since silicon is in the same column that C and bromine is in the same column that Cl, you predict that in the new formula Si replaces C and Br replaces Cl, leading to SiBr₄
