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Montano1993 [528]
4 years ago
13

Which astronomer spent 20 years plotting the positions of the planets?

Chemistry
1 answer:
devlian [24]4 years ago
3 0

Answer:

Tycho Brahe

Explanation:

Tycho Brahe spent 20 years in plotting the positions of the planets. He was among a group of astronomers who helped developing heliocentric model of the universe.

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What is the percent by volume of isopropyl alcohol in a solution made by mixing 120 mL of the alcohol with enough water to make
Elena L [17]

Answer: The percent by volume of isopropyl alcohol in a solution made by mixing 120 mL of the alcohol with enough water to make 350 mL of solution is 25.5%.

Explanation:

Given: Volume of solute = 120 mL

Volume of solvent = 350 mL

Now, total volume of the solution is as follows.

V_{total} = V_{solute} + V_{solvent}\\= 120 mL + 350 mL\\= 470 mL

Let us assume that 100 mL of solution is taken and the amount of isopropyl alcohol present in it is as follows.

\frac{V_{solute}}{V_{total}} \times 100 mL\\\frac{120 mL}{470} \times 100 mL\\= 25.53 mL

Hence, there is 25.53 mL isopropyl alcohol is present in 100 mL of solution. Therefore, %v/v is calculated as follows.

Percent (v/v) = \frac{25.53 mL}{100 mL}\\= 25.5%

Thus, we can conclude that the percent by volume of isopropyl alcohol in a solution made by mixing 120 mL of the alcohol with enough water to make 350 mL of solution is 25.5%.

7 0
3 years ago
The spontaneous reaction that occurs when the cell in the picture operates is as follows: 2Ag+ + Cd(s) ???? 2 Ag(s) + Cd2+ (A) V
Snowcat [4.5K]

Answer:

14. B    15. D    16. C     17. B

Explanation:

The spontaneous reaction that occurs when the cell operates is shown below:

2Ag^{+} + Cd_{(s)} ⇒2Ag_{(s)} + Cd^{2+}

We need to select the correct option from the list below for the following questions.

(A) Voltage increases. (B) Voltage decreases but remains > zero. (C) Voltage becomes zero and remains at zero. (D) No change in voltage occurs. (E) Direction of voltage change cannot be predicted without additional information.

14. A 50-milliliter sample of a 2-molar Cd(NO_{3})_{2} solution is added to the left beaker.

If a 50-milliliter sample of a 2-molar Cd(NO_{3})_{2}  solution is added to the left beaker, the voltage decreases but its value remains greater than zero. The correct option is B

15. The silver electrode is made larger.

If the silver electrode is made larger, no change in the value of the voltage since we don't have the idea of the initial value. The correct option is D.

16. The salt bridge is replaced by a platinum wire.

If the salt bridge is replaced by a platinum wire, there will be no passage of electrons because electrons can't pass through a platinum wire. Therefore, the voltage will be zero and remains at zero. The correct option is C.

17. Current is allowed to flow for 5 minutes.

If current is allowed to flow for 5 minutes, the voltage decreases but its value remains greater than zero. The correct option is B.

7 0
4 years ago
If you are playing pool and hit the cue ball at the stationary 8 ball, what should happen?
jolli1 [7]

Answer If a ball goes into a pocket and bounces back on to the playing surface, it is not considered pocketed. If it is the 8-ball, it is not a win. If it is the cue ball, it is not a scratch.

Explanation:

3 0
3 years ago
What are interactions between flip flops and sulfuric acid
frosja888 [35]
When the flip flops are used to walk on the ground the sulfuric acid from the ground overtime tends to wear down the bottom of the flip flops
3 0
3 years ago
Ok I really really really need help!!
joja [24]
_2k + _F2—> _2KF

put a 2 before the K and before the KF and you’re all good. it needed to be balanced with the F2
5 0
3 years ago
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