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Drupady [299]
3 years ago
9

The number of neutrons in the nucleus of an atom can be calculated by

Chemistry
1 answer:
Bess [88]3 years ago
6 0
3 mass number- proton number
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How many milliliters of a 3.4 M NaCl solution would be needed to prepare each solution?
Ksenya-84 [330]

Answer:

a. Approximately 1.3\; \rm mL.

b. Approximately 7.2\; \rm mL.

Explanation:

The unit of concentration "\rm M" is equivalent to "\rm mol \cdot L^{-1}", which means "moles per liter."

However, the volume of both solutions were given in mililiters \rm mL. Convert these volumes to liters:

\displaystyle 45\; \rm mL = 45\; \rm mL \times \frac{1\; \rm L}{1000\; \rm mL} = 0.045\; \rm L.

\displaystyle 330\; \rm mL = 330\; \rm mL \times \frac{1\; \rm L}{1000\; \rm mL} = 0.330\; \rm L.

In a solution of volume V where the concentration of a solute is c, there would be c \cdot V (moles of) formula units of this solute.

Calculate the number of moles of \rm NaCl formula units in each of the two solutions:

Solution in a.:

n = c \cdot V = 0.045\; \rm L \times 0.10\; \rm mol \cdot L^{-1} = 0.0045\; \rm mol.

Solution in b.:

n = c \cdot V = 0.330\; \rm L \times 0.074\; \rm mol \cdot L^{-1} = 0.02442\; \rm mol.

What volume of that 3.4\; \rm M (same as 3.4 \; \rm mol \cdot L^{-1}) \rm NaCl solution would contain that many

For the solution in a.:

\displaystyle V = \frac{n}{c} = \frac{0.0045\; \rm mol}{3.4\; \rm mol \cdot L^{-1}} \approx 0.0013\; \rm L.

Convert the unit of that volume to milliliters:

\displaystyle 0.0013\; \rm L = 0.0013\; \rm L \times \frac{1000\; \rm mL}{1\; \rm L} = 1.3\; \rm mL.

Similarly, for the solution in b.:

\displaystyle V = \frac{n}{c} = \frac{0.02442\; \rm mol}{3.4\; \rm mol \cdot L^{-1}} \approx 0.0072\; \rm L.

Convert the unit of that volume to milliliters:

\displaystyle 0.0072\; \rm L = 0.0072\; \rm L \times \frac{1000\; \rm mL}{1\; \rm L} = 7.2\; \rm mL.

8 0
3 years ago
2. Would you measure a pencil in meters? A hallway in millimeters? Discuss
Eduardwww [97]

Answer:

Measuring a pencil in meters would be very difficult, as a single meter is much longer than one pencil. Also, measuring a hallway in millimeters would be very difficult considering how small millimeters are in comparison to a hallway. However, if you switch these two then they would work very well.

5 0
3 years ago
Circle which of the following depend on the amount of matter present:
yan [13]
It is the boilimg point now aa
4 0
3 years ago
Which should be kept away from heat sources? Check all that apply.
Maru [420]

Answer:

loose hair, flammable clothing, and all stored chemicals especially flammable liquids., should be kept away from heat.

A fire blanket is a highly flame-resistant blanket that can be used to extinguish a small fire or to wrap around a person in case of a fire and water helps put it out too.

7 0
3 years ago
Read 2 more answers
A) if each substance above is heated at the same rate and same mass, which of the above has a smaller specific heat? how do you
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Answer:

I think B would be alcohol but A I'm not to sure

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3 years ago
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