-- I can calculate the formula mass but get confused with the various conversions between different types of units. I have the correct answers but I am trying to learn how to work through the problems to get the correct answer.
10) A sample of talc, Mg3Si4O10(OH)2, has a mass of 0.664 g. Calculate the number of mmoles of Mg3Si4O10(OH)2.
11) A sample of gypsum, CaSO4•2H2O, has a mass of 22 g. Calculate the number of moles of CaSO4•2H2O.
12) A sample of potassium dichromate, K2Cr2O7, has a mass of 578 Gg. Calculate the number of moles of K2Cr2O7.
13) A pure sample contains 660 moles of potassium dichromate, K2Cr2O7. What is the mass of the sample?
14) A pure sample contains 3.0 x 10-8 moles of gypsum, CaSO4•2H2O. What is the mass of the sample in units of ng?
15) A pure sample contains 8.8 x 10-2 moles of talc, Mg3Si4O10(OH)2. What is the mass of the sample?
16) A pure sample contains 1.5 moles of ammonium carbonate, (NH4)2CO3. What is the mass of the sample?
The answers are
10) 1.75 mmoles Mg3Si4O10(OH)2
11) 0.13 moles CaSO4•2H2O
12) 1.96 x 109 mol K2Cr2O7
13) 1.94 x 105 g K2Cr2O7
14) 5165 ng CaSO4•2H2O
15) 33.4 g Mg3Si4O10(OH)2
16) 144.1 g (NH4)2CO3
In: Chemistry
TYPED RESPONSE ONLY WITH AT LEAST 1 REFERENCE:
List four factors that can shift the position of an equilibrium.
Only one of these factors can alter the value of the equilibrium
constant. Which one is it?
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What is the percent dissociation of 1 L of 0.1000 M acetate buffer at pH 4.76 after the addition of 77.76 mL of 0.3201 M HClO4 ?
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In a constant-pressure calorimeter, 60.0 mL of 0.310 M Ba(OH)2 was added to 60.0 mL of 0.620 M HCl. The reaction caused the temperature of the solution to rise from 22.61 °C to 26.83 °C. If the solution has the same density and specific heat as water (1.00 g/mL and 4.184 J/g·°C, respectively), what is ΔH for this reaction (per mole of H2O produced)? Assume that the total volume is the sum of the individual volumes.
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1) You are a research scientist studying a novel enzyme X, and you want to characterize this new enzyme. You measure the velocity of the reaction with different substrate concentrations and get the following data:
| [S] (mM) | Initial Velocity (mmol/min) |
| 3.0 | 10.4 |
| 5.0 | 14.5 |
| 10.0 | 22.5 |
| 30.0 | 33.8 |
| 90.0 | 40.5 |
a) Graph the above data. From the graph, estimate KM and Vmax (Michaelis-Menten Plot)
b) Use Lineweaver-Burk plot to calculate Km and Vmax. Show all equations and calculations.
c) You decide to do this experiment again, but this time with only one third of the enzyme X concentration used in the first experiment. Draw a new graph on the same graph that you did the first graph on. Estimate Km and Vmax from the new graph.
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Sodium fluoride and lead nitrate are both soluble in water. If 0.0946 g of NaF and 0.362 g of Pb(NO3)2are dissolved in sufficient water to make 1.50 L of solution, will a precipitate form? How do you know if there should be a precipitate or not? What is the chemical formula for the possible precipitate? The Ksp for lead fluoride is 3.7 x 10-8.
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Explain the spectral differences between the spinach and the Cordyline fruticose leaves.
What determines the leaf color in plants? Provide a structure and of the molecule and explain why green is the predominant color.
Why do deciduous trees change color in the fall (biochemical explanation). Provide a molecule responsible for yellow and one for red color. Why are these molecules necessary in addition to the chlorophyll?
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Here we have a Radioactive Thermoelectric Generator (RTG) that is powered by Plutonium 238 (238Pu). The RTG produces 1400 Watts. 238Pu decays by alpha-particle emission. The alpha-particle has 5.593 MeV of kinetic energy. The half life (t1/2) of 238Pu is 87.7 years.
a) Write the nuclear reaction for 238Pu decay
b) Assume all of the kinetic energy is converted to heat. How much 238Pu (in grams) must be present to produce 1400 Watts of power?
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1. A student prepares a 250.0 mL solution using 41.7 grams of potassium nitrite. They then take 29.9 mL of this solution and dilute it to a final volume of 250.0 mL. How many grams of potassium nitrite are in a 36.2 mL sample of this final diluted solution?
2.
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If you wanted to make a 4.50 M solution of aluminum nitrate using a 400.00 mL volumetric flask, how many grams of this salt would you need to use? 3. H2SO4 + 2KOH → 2H2O + K2SO4 How many mL of a 1.75 M solution of potassium hydroxide are required to titrate 15.72 mL of a 2.13 M solution of sulfuric acid? |
In: Chemistry
Part A
A beaker with 195 mL of an acetic acid buffer with a pH of 5.000 is sitting on a benchtop. The total molarity of acid and conjugate base in this buffer is 0.100 M. A student adds 4.50 mL of a 0.430 M HCl solution to the beaker. How much will the pH change? The pKa of acetic acid is 4.740.
In: Chemistry
Write the total differential for H as a function of T & P and derive the appropriate working equation.
In: Chemistry
find the ph of each mixture of acids
0.020m HNO3 and 0.225 Mbr
0.095m in acetic acid and 0.075.m in H2SO4
0.0500 M in HCL04 and 0.02 M HBR
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Calcium nitrate and ammonium flouride react to form calcium flouride, dinitrogen monoxide, and water vapor. What mass of each substance is present after 21.83g of calcium nitrate and 22.75g of ammonium flouride react completely?
when 75.5g of calcium and 43.1g of nitrogen gas undergo a reaction that has a 88% yield, what mass of calcium nitride forms?
when 73.8g of calcium and 41.8g of nitrogen gas undergo a reaction that has a 92.4% yield, what mass of calcium nitride forms?
a sample of 0.767 mol of a metal m reacts completely with excess flourine to form 59.9g of MF2. what element is represented by the symbol M?
when 29.8g of methane and 47.6 g of chlorine gas undergo a reaction that has a 74.5% yield, what mass of chlormethane (CH3cl) forms?
In: Chemistry
Can you have TSS without turbidity? Can you have turbidity without TSS? Explain why based on the physics of the measurement.
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1a )When 50.0 mL of 0.500 M HCl at 25.0°C is added to 50.0 mL of 0.500 M NaOH at 25.0°C in a coffee cup calorimeter, the temperature of the mixture rises to 28.2°C. What is the enthalpy of reaction per mole of acid? Assume the mixture has a specific heat capacity of 4.18 J/(g ? K) and that the densities of the reactant solutions are both 1.00 g/mL.
1b) Consider the following reaction: 2 PbS (s) + 3 O2 (g) ? 2 PbO (s) + 2 SO2 (g) ?H = -827.4 kJ How many grams of PbS have reacted if 975 kJ of heat is produced? 1c) Consider the following reaction carried out under constant pressure 3MgO(s) + 2NH3(g) ? 3H2O(l) + Mg3N2(aq) ? Hrxn = 5.78×102 kJ Calculate the heat associated with the complete reaction of 46.0 g of MgO with 17.1 g of NH3.
In: Chemistry