Which of the following best describes Newton's First Law of Motion? (more than one answer applies)

How many protons and neutrons are in the nucleus of isotope with mass of 68.926 amu?

atroni [7]

Isotopes are atoms of the same element with the same number of protons and same number of electrons but with different number of neutrons. They differ in the number of neutrons that is why they also differ in mass numbers. Since they have the same number of protons, they have the same atomic number.
For instance, when the nucleus of the isotope with a 68.926 amu, there are 30 protons and 39 neutrons in the nucleus. The best example for this is Zn (zinc-69 isotope) and Ga (gallium-69 isotope) which has 68.926 amu and 68.925 amu respectively.

3 0

4 years ago

Which of the following best describes a vacuum? Hot Cold Shiny Empty

wel

Answer:

shiny

Explanation:

4 0

3 years ago

Read 2 more answers

Calculate the weight percent of ascorbic acid in a tablet of Vitamin C from the following data:A 80 mg sample of a crushed Vitam

Lina20 [59]

Answer:

The Answer is 88%

Explanation:

The balanced ionic equation of the reaction

$IO^{3- }+ 8 I^- + 6 H^+ => 3 I^{3- }+ 3 H_2O$

$I^{3-} + 2 S_2O_3^{2-} => 3 I^- + S_4O_6^{2-}$

$C_6H_8O_6 + I^{3- }+ H_2O => C_6H_6O_6 + 3 I^- + 2 H^+$

Looking at the above reactions

The original number of moles of $I^{3-}$ = 3 × number of moles of $IO^{3-}$

= 3 × volume × concentration of $KIO_3$

Note: The formula for number of moles is volume × concentration

$=3 * \frac{40}{1000} * 0.00653 =0.000784$ mol

The number of moles of $I^{3-}$ left after its reaction with ascorbic acid

= $\frac{1}{2}$ x moles of $S_2O_3^{2-}$

= $\frac{1}{2}$ x volume x concentration of $S_2O_3^{2-}$

$= \frac{1}{2} * \frac{15}{1000} * 0.0510 =0.000383 \ mol$

Note: The division by 1000 is to convert mill liter to liter

Moles of ascorbic acid = moles of $I^{3-}$ reacted

$= initial \ moles \ of \ I^{3-} \ - remaining \ moles \ of \ I^{3-}$

$=0.000784 - 0.000383$

$=0.000401 \ mols$

$Mass = moles \ * molar \ mass$

Hence

Mass of ascorbic acid = moles of ascorbic acid × molar mass of ascorbic acid

$= 0.000401* 176.12 = 0.07055\ g$

$= 70.55\ mg$

Weight% of ascorbic acid = mass of ascorbic acid/mass of sample x 100%

= 70.55/80 × 100%

= 88.1%

3 0

4 years ago

A 360. mg sample of aspirin, C9H8O4, (molar mass 180. g), is dissolved in enough water to produce 200. mL of solution. What is t

Gemiola [76]

Answer:

Molarity = 0.01 M

Explanation:

Molarity is used to measure the concentration of a solution. It will be same for the whole solution or a small amount of solution if the solution is homogeneous.

So, Molarity of 200 mL of solution = Molarity of 50 mL of solution

$\mathbf{Molarity = \frac{number \ of \ moles \ of \ solute}{Volume \ of \ solution \ (in \ liters)}}$