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3 years ago

Gold atoms can be identified based on the number of which subatomic particles?

Chemistry

2 answers:

sp2606 [1]3 years ago

7 0

Answer: A

Explanation:

A Gold (Au) atom has 79 protons and 79 electrons. A typical gold atom has 118 neutrons, though there are 18 other radioisotopes discovered so far. 79 is its charge (atomic number), which is both its proton number and electron number

dalvyx [7]3 years ago

6 0

D. Protons, if you change the number of protons you change the element. You cannot change nuclei. You can have the same element with different numbers of neutrons (isotopes) and different numbers of electrons (ions). So protons will allow you to identify the element.

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Calculate the percent by volume of a solution that has 75 mL of solute dissolved in 375 mL of solution. Show your work and round

Mandarinka [93]

Answer:

The answer is 20 % V/V

Explanation:

We use this formula for calculate the %V/V:

%V/V= (ml solute/ml solution) x 100= (75ml/375 ml)x 100 = 20 % V/V

<em>The% V / V represents the amount of ml of solute dissolved in 100 ml of solution</em>

7 0

3 years ago

A chemist prepares a solution of magnesium chloride MgCl2 by measuring out 49.mg of MgCl2 into a 100.mL volumetric flask and fil

Flura [38]

Answer: Molarity of $Cl^-$ anions in the chemist's solution is 0.0104 M

Explanation:

Molarity : It is defined as the number of moles of solute present per liter of the solution.

Formula used :

$Molarity=\frac{n\times 1000}{V_s}$

where,

n= moles of solute

$Moles=\frac{\text{Given mass}}{\text{Molar mass}}=\frac{0.049g}{95g/mol}=5.2\times 10^{-4}moles$

$V_s$ = volume of solution in ml = 100 ml

Now put all the given values in the formula of molarity, we get

$Molarity=\frac{5.2\times 10^{-4}moles\times 1000}{100ml}=5.2\times 10^{-3}mole/L$

Therefore, the molarity of solution will be $5.2\times 10^{-3}mole/L$

$MgCl_2\rightarrow Mg^{2+}+2Cl^-$

As 1 mole of $MgCl_2$ gives 2 moles of $Cl^-$

Thus $5.2\times 10^{-3}$ moles of $MgCl_2$ gives = $\frac{2}{1}\times 5.2\times 10^{-3}=0.0104$

Thus the molarity of $Cl^-$ anions in the chemist's solution is 0.0104 M

6 0

3 years ago

7. Which of the following changes could be associated with either a chemical change OR a

Elan Coil [88]

Answer:

a: chemical change because the change cannot be reversed.

b: physical change because the action can be reversed.

c: chemical change.

d:chemical change.

any change that cannot be reversed is a chemical change and any change that can be reversed is a physical change.

5 0

2 years ago

how to determine the net charge of the tripeptide Asp-Gly-Leu at pH 7. Can someone show in details and tricks on how to solve it

Ugo [173]

Answer:

Explanation:

You need to search your pKa values for Asn (2.14, 8.75), Gly (2.35, 9.78) and Leu(2.33, 9.74), the first value corresponding to -COOH, the second to -NH3 (a third value would correspond to an R group, but in this case that does not apply), and we'll build a table to find the charges for your possible dissociated groups at indicated pH (7), we need to remember that having a pKa lower than the pH will give us a negative charge, having a pKa bigger than pH will give us a positive charge:

-COOH -NH3

pH 7------------------------------------------------------

Asn - +

Gly - +

Leu - +

Now that we have our table we'll sketch our peptide's structure:

This will allow us to see what groups will be free to react to the pH's value, and which groups are not reacting to pH because are forming the bond between amino acids. In this particular example only -NH group in Ans and -COOH in Leu are exposed to pH, we'll look for these charges in the table and add them to find the net charge:

+1 (HN-Asn)

-1 (Leu-COOH)

The net charge is 0!

I hope you find this information useful and interesting! Good luck!

5 0

3 years ago

What is the force exerted by the load being lifted is called?

ludmilkaskok [199]

Hey!!

here is your answer >>>

The answer for your question is the tension. We lift it up and the tension is exerted by the object downwards!.

Hope my answer helps!

8 0

3 years ago