Robert uses a spring scale to measure force. What are the units of his measurements? A. Pascals B. Volts C. Joules or D. Newtons

How many gold atoms are in an 0.333 ounce, 18 k gold bracelet? (18 k gold is 75% gold by mass.)?

taurus [48]

<span>0.333 ounce * 0.75 * 28.35 grams/ounce = 7.080 grams gold 7.080 grams Au / 196.967g/mol Au = 0.0359 mol Au 0.0359 mol Au * (6.023 * 10^23) atoms/mol = 2.24 * 10^22 Atoms Au</span>

7 0

3 years ago

Iron (Fe) has three isotopes. Calculate the average atomic mass of the element Fe using the following data: Isotope atomic mass

Maksim231197 [3]

Answer:

Average atomic mass = 55.83 amu

Explanation:

The formula for the calculation of the average atomic mass is:

$Average\ atomic\ mass=(\frac {\%\ of\ the\ first\ isotope}{100}\times {Mass\ of\ the\ first\ isotope})+(\frac {\%\ of\ the\ second\ isotope}{100}\times {Mass\ of\ the\ second\ isotope})+(\frac {\%\ of\ the\ third\ isotope}{100}\times {Mass\ of\ the\ third\ isotope})$

Given that:

For first isotope, Fe-54:

% = 6 %

Mass = 53.94 amu

For second isotope, Fe-56:

% = 92 %

Mass = 55.93 amu

For third isotope, Fe-57:

% = 2 %

Mass = 56.94 amu

Thus,

$Average\ atomic\ mass=\frac{6}{100}\times {53.94}+\frac{92}{100}\times {55.93}+\frac{2}{100}\times {56.94}$

<u>Average atomic mass = 55.83 amu</u>

5 0

3 years ago

The ground state of an electron is the least stable energy state of an atom

kari74 [83]

Answer:

electron configuration

Explanation:

The arrangement of electrons in the atomic orbitals of an atom is called the electron configuration. Electron configurations can be determined using a periodic table.

6 0

3 years ago

List a possible set of four quantum numbers (n,l,ml,ms) in order, for the highest energy electron in gallium?

Elena-2011 [213]

Gallum: Z = 31

electron configuration: [Ar] 4s^2 3d10 4s2 4p1

Highest energy electron: 4p1

Quantum numbers:

n = 4, because it is the shell number
l = 1, it corresponds to type p orbital
ml = may be -1, or 0, or +1, depending on space orientation, they correspond to px, py, pz
ms = may be -1/2 or +1/2, this is the spin number.

7 0

3 years ago

A chemist has some 40% acid solution, some 60% acid solution, and a wholebunch of free time. How many liters of each should be u

TiliK225 [7]

Answer:

30 Liters of 40% acid solution and 10 L of 60% acid solution is needed.

Explanation:

Let volume of the 40% acid solution be x.

Let volume of the 60% acid solution be y.

Volume of solution formed after mixing both solution = 40 L

x + y = 40 L..[1]

Volume of acid 40% solution = 40% of x= 0.4x

Volume of acid 60% solution = 60% of y= 0.6y

Volume of acid formed = 45% of 40 L = $\frac{45}{100}\times 40=18L$

$0.4x+0.6y=18 L$ ..[2]

Solving [1] and [2]

x = 30 L , y = 10 L

30 Liters of 40% acid solution and 10 L of 60% acid solution is needed.

8 0

3 years ago