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stiv31 [10]
2 years ago
11

A collection of pennies was investigated. 10.00% were found to have been minted in San Francisco with an average mass of 2.15 g

and 90.00% we’re minted in in Philly with an average mass of 2.156 g. What was the average mass of pennies in this sample? Give the correct answer with the proper amount of significant figures
Chemistry
1 answer:
german2 years ago
5 0

The average mass of the pennies in the sample is 2.16 g.

We have a set of pennies from which 10.00% have an average mass of 2.15 g and 90.00% have an average mass of 2.156 g. The average mass (am) of the whole set is a weighted average, that considers the mass (m) and the percentage (perc) of each group. We can calculate it using the following expression.

am=\frac{\Sigma m \times perc  }{100 \%} = \frac{2.15g \times 10.00\% + 2.156 g \times 90.00\% }{100\%} = 2.1554 g \approx 2.16 g

The average mass of the pennies in the sample is 2.16 g.

You can learn more about weighted average here: brainly.com/question/18554478

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For ΔH soln to be very small, what quantities must be nearly equal in magnitude? Will their signs be the same or opposite?
eimsori [14]

A solute dissolves in excess solvent to form a solution:

                            solute + solvent → solution

<h3>What is the Enthalpy and their relation ? </h3>

A thermodynamic system's enthalpy, which is one of its properties, is calculated by adding the system's internal energy to the product of its pressure and volume. It is a state function that is frequently employed in measurements of chemical, biological, and physical systems at constant pressure, which the sizable surrounding environment conveniently provides.

A solution is a uniform mixture of two or more components that can exist in the solid, liquid, or gas phases. The amount of heat that is released or absorbed during the dissolving process is known as the enthalpy change of solution (at constant pressure).

There are two possible values for this enthalpy of solution ( H solution ) : positive (endothermic) and negative (exothermic). It is most straightforward to visualize a hypothetical three-step process occurring between two substances while trying to grasp the enthalpy of solution. The solute is one substance; let's call it A. The solvent is the second component; let's call it B.

The initial procedure exclusively affects the solute A and calls for disabling all intramolecular forces holding it together. This indicates that the molecules of the solute separate. This process' enthalpy is known as H1. Since breaking interactions requires energy, this is always an endothermic process, hence H1>0.

Their sign will be opposite.

To know more about Enthalpy please click here : brainly.com/question/14047927

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5 0
2 years ago
If you have a solution that is 15 percent by mass of KCl in benzene, what is the new boiling point?
Serhud [2]

Answer:

https://www.chegg.com/homework-help/questions-and-answers/1-10-points-solution-15-percent-mass-kcl-benzene-new-boiling-point--901-c-b-921-c-c-821-c--q63751186

Explanation: Thats your answer

3 0
2 years ago
Drawing Conclusions
Dmitrij [34]

<u>Answer:</u>

<em>The situation given here is imaginary such that the life of Rock has to be found using the half-life of the element lokium that has been found inside the rock. </em>

<u>Explanation:</u>

Half-life of any material is the amount of time taken by that particular material to decay. Now the amount of lokium found in rock can show after how many half-lives this amount has been left out.

The time elapsed will be log (L) atoms X half-life.

4 0
3 years ago
Which best describes a compound such as sodium chloride?
gayaneshka [121]

Answer:

check it below

Explanation:

NaCl; Sodium Chloride is an ionic compound formed by sodium and Chlorine.

Ionic bond is very strong, It can't be separated back to sodium and chlorine just by physical change. Chemicals which are more reactive can displace ions, thus seperate it

5 0
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I took my test and it was right

3 0
3 years ago
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