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Stoichiometry

Brackett Series

1) Lines in the Brackett series of the hydrogen spectrum are cause by emission of energry accompanying the fall of an electron from outer shells to the fourth shell. The lines can be calculated using the Balmer-Rydberg equation. See Attachement for equation where m = 4, R = 1.097 x 10-2nm-1 , and n is an integer greater th

Density

Nickels are composed of 25% nickel and 75% copper by mass, what is its density (d of nickel = 8.902 g/cm3; d of copper = 8.95 g/cm3)?

Particles

The environmental protection agency (EPA) has proposed a new standard for microparticulates in air: For particles up to 2.5 um in diameter, the maximum allowable amount is 50 ug/m3. If your 9.2 ft x 13.8 ft x 8.6 ft dorm room just meets the new EPA standard, how many of these particles are in your room? (Assume the particles are

Molecular mass and moles

First, how many moles are present in each of the following masses? 2.58g of SrSO4 and 2.53 x10-3g of Ag2CO3. Second, going in reverse, How many grams are necessary to obtain the given number of moles? 3.20 x 10-4 moles of NaOH and 6.42 moles of AgNO3.

Hydroxide ion concentration using K or Kw not Ksp

At 25 degrees C, 0.212 g of barium hydroxide Ba(OH)2 (2 in lower position) is dissolved completely in sufficent water to make 0.25 litre final solution. What is the hydroxide ion concentration(in mol per litre) in this solution? Give the answer in scientific notation to an appropriate number of significant figures, and sta

Osmotic pressure and molar mass

An aqueous solution of 10.00 g of an enzyme has a volume of 1.00 L at 29°C. The solution's osmotic pressure at 29°C is found to be 0.781 torr. Calculate the molar mass of the enzyme.

Reactions and Moles

How many moles of water are made from the reaction of 2.2 moles of oxygen gas with unlimited quantities of hydrogen gas? Given the reaction:2H2 + O2 > 2H2O

Molarity of a solution

What is the molarity of a solution formed from 20.0 grams of NaCl dissolved in 650.0 mL of H2O?

Nickel Chloride and Sodium Phosphate Reaction

1. Nickel(11) chloride reacts with sodium phosphate to produce nickel(11) phosphate and sodium chloride. NiCl2(aq) + Na3PO4(aq) -----> Ni3(PO4)2 (s) + NaCl(aq) a. Balance the equation above b. Using the balanced equation, find out how many moles of nickel(11) chloride are required to produce 0.479 mol of nickel

Empirical & Molecular Formula

When phosphorus is burnt in a free supply of air, diphosphorous pentoxide is formed. During later stages of combustion in a limited supply of air, the flame becomes larger greenish and flickering. Another phosphorus oxide is formed which is a white waxy crystalline solid which melts @ 23.8 degrees C and becomes a gas @ 176 degre

Air bags

Air bags are activated when a severe impact causes a steel ball to compress a spring & electrically ignite a detonator cap. This causes sodium azide(NaN3) to decompose explosively: 2NaN3(s) = 2Na(s) + 3N2(g) What mass of NaN3(s) must be reacted to inflate an airbag to 70.0 L. at STP?

Show work-Oswald process - mass and how much oxygen required?

9) Industrially, nitric acid (HNO3) is produced by the Oswald process represented by the following - what mass of NH3 is needed to produce 5 tones of HNO3? How much Oxygen is required? 4NH3 + 5O2 = 4NO = 6H20 2NO + O2 = 2NO2 2NO2 + H2O = HNO3 + HNO2

Chemical equation with 7 parts

(Any number following an asterisk is a subscript.) Using the balanced chemical equation: C*6H*12O*6 + 2H(positive charge)--> C*6H*14O*6 answer the following A. How many grams of C*6H*12O*6 equals one mole? B. How many grams of C*6H*14O*6 equals one mole? C. How many moles of H(positive charge) react with 1 mol of C*6H*12O*

A equation with 9 parts

(any number following an asterisk is a subscript) Using the equation for the combustion of methane: CH*4(L) + O*2(G) --> CO*2(G) + H*2O(G) answer the following: A. Is the equation properly balanced and if not balance it. B. Name the compounds in this reaction. c. How many moles of O*2 react with 1 mol of CH*4? D. How many

This deals with limiting reactants in stoichiometry

If 350.0 mL of 6.00 M H2SO4 reacts with 45.00 grams of Al in the following reaction, what is the limiting reagent, how many moles of excess reagent will there be, and how many liters of H2 will form? The reaction is: H2SO4 + Al produces Al2(SO4)3 + H2 If you could please show the steps, I'd appreciate it.

Stoichiometry problem dealing with limiting reagents

If 275.0 mL of 0.5000 M ZnCl2 reacts with 1.650 x 10 to 23rd power of AlPO4 compounds in the following reaction, what is the limiting reagent, how many moles of excess reagent will there be, and how many grams of each product will form? 3 ZnCl2 + 2 AlPO4 yields Zn3(PO4)2 + 2 AlCl3 I am substitute teaching, and I would lik

Calculating Molarity and Molality

Question: A sodium chloride solution has a molarity of 1.250 mol/L and a density of 1.050 g/ml. Calculate molality, the mole fraction of water, and the percent by mass of sodium chloride.

Solve: Distance, Velocity, Density and Volume

Questions: 1. If the sun which is 93,000,000 miles away away from Earth was to go out, how long would it take for us to know that this had happened? Light travels at a speed of 3 x 10^8 meters/second. 2. What would the density be (in g/cm^3) of a block that is 4 cm by 15 cm by 12 cm, and has a mass of 4.3 kg? 3. An ob

Mass Balance Problem

Please see the attached file for full problem description. --- Q1. Starting with a pulp with a water content of 99%, how much water must be removed to obtain one ton of paper containing 60% water? Solution. Water removed Pulp

Molarity

5. Calculate the sodium ion concentration when 60.0 mL of 6.0 M sodium carbonate is added to 30.0 mL of 1.0 M sodium bicarbonate.

Density

A cylindrical bar of gold that is 1.5 in. high and 0.25 in. in diameter has a mass of 23.1987g, as determined on an analytical balance. An empty graduated cylinder is weighed on a triple beam balance and has a mass of 73.7g. After pouring a small amount of liquid into the graduated cylinder, the mass is 79.16g. When the gold cyl

Chemistry Problems

1. The following reaction occurs: CaCO3 + 2H- -> Ca2+ + CO2 +H2O If a 25gm sample of calcium carbonate is added to a 75.5 ml HCl (density = 1.125gm/cm3, 26% HCl by mass), calculate the molarity of the HCL remaining in solution (if any) after the reaction is complete. Assume no volume change. 2. A sample of coc

Conc. of an ideal solution as function of T and position in a strong gravit. field

An ideal solution with solute density 1.05 and solvent density 1.00 is subject to a huge gravity force field, a linear function of postition, F=kr, k is a constant and r is the position along the field. Derive the concentration as a function of T and position r along the field. (Hints: express gravitational potential as functi

Finding limiting reactant, theoretical yield, and actual yield

An electric furnace produces phosphorus by the following reaction: Ca3(PO4)2(s) + C(s)+SiO2(s)= CaSiO3(s)+CO(g)+P(I) An initial reaction mixture contains 1500g calcium phosphate, 250 g carbon and 1000g silicon dioxide. a) What is the limiting reactant? b) What is the theoretical yield of phosphorus? c) After the reaction

Physics

Imagine that we give N2(+), O2(+) and (NO)+ ions the same velocity of 30.0 km/s and then send them into a mass spectrometer where the magnetic field strength is B=8.5MN/C. How far would the spot on the photographic plate be from the entry point for each ion, assuming that each ion completes one-half of an orbit. The atomic mas

Simplest Formula Analysis

50.0 g of an oxide of Chromium (Cr) was found to contain 13.28g of potassium (K), 17.68 g of Chromium (Cr) and 19.04 g of oxygen (O). Find the simplest formula...