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23 Nov 2019

Lead metal can be extracted from a mineral called galena, whichcontains 86.6% lead by mass. A particular ore contains 68.5% galenaby mass.

If the lead can be extracted with 92.5% efficiency, what mass ofore is required to make a lead sphere with a 5.50 cm radius?

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Trinidad Tremblay
Trinidad TremblayLv2
15 Jan 2019

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Related questions

A--Galena (also known as lead (II) sulfide) is the ore from which elemental lead is extracted. In the first step of the extraction process, galena is heated in oxygen to form lead (II) oxide and sulfur dioxide.

--Write a balanced equation for the reaction. (2 points)
--What mass of galena is converted to lead (II) oxide if 975 kJ of heat is produced? (3 points)

B--Tungsten(VI) oxide reacts with hydrogen gas (H2) to produce tungsten metal and water vapor. The equations below represent the enthalpy change for the formation of the two compounds from their elements.

2 W (s) + 3 O2 (g) ---> 2 WO3 (s) ΔH = -1685.4 kJ

2 H2 (g) + O2 (g)---> 2 H2O (g) ΔH = -477.84 kJ

--Write a balanced equation for the reaction. (1 point)

--What is the enthalpy change for the overall reaction written in (a)? (4 points)

C---An important step in the synthesis of nitric acid is the reaction of ammonia (NH3) and molecular oxygen to form nitrogen monoxide gas and water vapor.

--Write a balanced equation for this reaction. (2 points)

--Calculate DHo for this reaction, using standard heat of formation values from Appendix G in the Open Stax Chemistry text. (3 points)

D----When an electron in a 2p orbital of a particular atom makes a transition to the 2s orbital, a photon of approximate wavelength 629.1 nm is emitted. What is the energy difference between these 2p and 2s orbitals?

E---Provide a numerical value (whole number) for each of the following questions. Briefly explain your reasoning (1 point each).

How many electrons can be contained in all of the orbitals with n = 4?

Among the orbitals with n = 4 (see part a), which one has the highest energy and how do you know this?

What is the l quantum number for a 4s orbital?

How many electrons can be described by the quantum numbers n = 3, l = 3, ml = 1?

l = 3, how many electrons can be contained in all the possible orbitals of a given principal quantum number?

(a) After the label fell off a bottle containing a clear liquid believed to be benzene, a chemist measured the density of the liquid to verify its identity. A 25.0-mL portion of the liquid had a mass of 21.95 g. A chemistry handbook lists the density of benzene at 15 °C as 0.8787 g/mL. Is the calculated density in agreement with the tabulated value? (b) An experiment requires 15.0 g of cyclohexane, whose density at 25 °C is 0.7781 g/mL. What volume of cyclohexane should be used? (c) A spherical ball of lead has a diameter of 5.0 cm. What is the mass of the sphere if lead has a density of 11.34 g/cm3? (The volume of a sphere is (4/3) πr3, where r is the radius.)

Calculated density corresponds to the benzene, so an unknown liquid is benzene.

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There are two stable isotopes of supposium (Su). Su-191=190.9609u(27.30%) Su-194=193.9633 u(72.70%) Compute the atomic mass ofsupposium.
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Which would not be found with a mass spectrometer.
a. the atomic mass of a single isotope of potassium
b. the number of stable isotopes of potassium c.the mass of aproton
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How many protons, neutrons, and electrons are in 24 Mg2+?
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a. 10 protons, 12 electrons, 24 neutrons b. 12 protons, 10electrons, 12 neutrons
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1.The age of rocks is sometimes calculated from the measured excessof lead 206 atoms over the normal abundance. The uranium isotopeU-238 decays to lead-206.What is the percent abundance of lead-206if there aare 4.52 X 10^21 atoms of lead-206 in a 198 g sample ofore that is 2.58% lead? a. 27.7 b. 0.0202 c. 4.70 x 10^-3 d. 30.4e. 0.782

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5 B(10.00 u) and 11
5 B (11.00 u). What is the natural percent abundance of B?
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3. 57.7 g Ni contains how many atoms? a. 3.47x10^23 b.0.983 c. 1.24x 10^24
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4. What mass of magnesium is necessary to make 10.5 g of magnesiumbromide if 1.04 g of magnesium makes 7.88 g of magnesiumbromide?
a. 7.89 g b. 1.39 g c. 79.9 g d. 3.66 g e. 1.58 g



5. How many atoms of lead are required to cover a 33.0 cm by 45.0cm area witha sheet of lead that is 0.140 mm thick? The density oflead is 11.35 g/cm3.
a. 1.42x10^26
b. 2.29x10^25
c. 6.86x10^22
d. 2.29x10^26
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6. The natural abundance of calcium in the earth's crust is 3.4% bymass. How many calcium atoms are present in a 1.50 g sample of theearth's crust?
a. 7.7x10^22 b. 7.7x10^20 c. 3.1x 10^22 d.6.6x10^23 e.5.1x10^20


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a. 85.7 u
b. 88.3 u
c. 86.1 u
d. 89.4 u
e. 87.1 u

10. Which is the more abundant isotope, CI-35 or CI37?
a. CI-17
b. CI-37
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d. CI-35
e. A third unstable isotope is more abundant

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69.9243 20.52%
71.9217 27.43%
72.9234 7.76%
73.9219 36.54%
75.9214 7.76%
The element is which of the following
a. Se b. Ge c. Ga d. As e. Zn

12. Lead-206 has a relative abundance of 23.6%. What sized block oflead (in cubic centimeters) will contain 8.34x10^21 atoms oflead-206? The density of lead is 11.35 is g/cm3.
a. 0.253
b. 0.0107
c. 1.07
d. 12.1
e. 0.330

13. When decomposed chemically, 73.0 grams of a sample of HCIproduce 71.0 g of Cl2 and 2.0 g of H2, while 34.0 g of a sample ofH2s produce 32.0g of S and 2.0g of H2. This is an example of theLaw:
a. of Definate Proportions
b. E=mc^2
c. of multiple proportions
d. of Conservation of Mass
e. none of these

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