IRA

Chlorophyll, the green pigment in leaves, has the formula C55H72MgN4O5. If 4.5g of Mg is available to a plant for chlorophyll synthesis, how many grams of carbon will be required to completely use up the magnesium? (enter only your numeric answer, not in...

5 years ago

Question: If we mix together 32.2 g of salicylic acids with 15.6 g of acetic anhydride in this reaction we obtain 27.8grams of asprin. What is the percent yield for this reaction? - enter only your numeric answer, do not include the % sign in your answer,...

5 years ago

Formula: CaCO3(s) + HCl(aq) --> CO2(g) + CaCl2(aq) + H2O How many grams of CO2 can be made by reacting 125 g of CaCO3 with 125 grams of HCl?

5 years ago

Consider the reaction 2H2 + O2 --> 2H2O What is the mass of water produced when 11.0 grams of O2 reacts with excess H2? Is the answer 22.0 grams of H2O? That's what I got

5 years ago

A white powder used in paints, enamels, and ceramics has the following percentage composition Ba = 69.6%, C = 6.09% and O = 24.3%. What is the subscript associated with Carbon in the empirical formula for the compound?

5 years ago

What are the subscripts associate with C, H and O when a 5.048g sample of a compound undergoes combustion to produce 7.406g of CO2 and 3.027g of H2O ? The answer I got was C1, H2, and O3

5 years ago

A solution of sodium sulfate was treated with 0.29M Barium Chloride solution until all the sulfate ion had reacted. The reaction required 32.16mL of the Barium Chloride solution. How many grams of Sodium sulfate were in the solution?

5 years ago

1) Substances that dissociate nearly 100% in solution to produce a conducting solution of ions are called _______________ 2) Substances that dissociate only a small extent in solution to produce a conducting solution of ions are called _______________ 3)...

5 years ago

Which of the following are considered insoluble? PbI2 NaNO3 Na2S Mg(OH)2 NH4OH AgCl

5 years ago

The substance that causes oxidation by accepting electrons is called 1) _____________ and the substance that causes reduction by donating electrons is called 2) ____________

5 years ago

If a reaction requires 0.13moles of NaNO3, how many milliliters of 1.73M NaNO3 are needed?

5 years ago

When the following equation is balanced in an acidic solution how many electrons are transferred? MnO4- + H2SO3 --> SO42- + Mn2+

5 years ago

A 0.429-g sample of gas occupies 125 mL at 60. cm of Hg and 25°C. The molar mass of the gas is ________ g/mol?

5 years ago

Barometric pressure changes are used by meteorologists to forecast short-term changes in the weather and are reported in units of inches of mercury. If the local barometric pressure is 22.66 inches of mercury (1 inch = 2.54 cm exactly), calculate the pres...

5 years ago

You are given a solution that contains one of the ions Ag+, Pb2+ or Ba2+. Develop a procedure to determine which ion is present. More than one reaction may be required to discover the ion’s identity. Explain how your procedure will determine the identity...

5 years ago

When iron (Fe) rusts (reacts with O2), the product is iron(III) oxide (Fe2O3). If 25 g Fe is reacted with 25 g O2 in a sealed container, what are the masses of Fe, O2 and Fe2O3 in the container after the reaction is complete? How is type of question calcu...

5 years ago

Rubidium has two naturally occurring isotopes: 85Rb and 87Rb. The natural abundance of 85Rb is 72.165% and it has an isotopic mass of 84.9118 u. Calculate the isotopic mass of 87Rb

5 years ago

A 125 mL flask contains 75 kPa Cl2 at 22 ˚C. (a) How many moles of Cl2 are in the flask? (b) What mass of Cl2 is in the flask?

5 years ago

4. Vitamin C, M= 176.12 g/mol, is a compound of composed of carbon, hydrogen, and oxygen. Vitamin C is found in many natural sources especially citrus fruits. When a 1.000-g sample of vitamin C is burned in a combustion apparatus 1.50 g of CO2 and 0.410 g...

5 years ago

The lines in the visible portion of the hydrogen spectrum are called the Balmer series, for which m=2 in the Rydberg equation. Calculate the wavelength in nanometers of the spectral line in this series for which n=4.

4 years ago

An energetically excited hydrogen atom has its electron in a 5f subshell. The electron drops down to the 3d subshell, releasing a photon in the process. What wavelength of light (in nm) is emitted by the process?

4 years ago

Mycobacterium tuberculosis, the organism that causes tuberculosis can be completely destroyed by irradiation with UV light with a wavelength of 254nm. What is the frequency of this radiation in scientific notation?

4 years ago

Give the 4 quantum numbers for the highest energy electron in the valence shell of Osmium.

4 years ago

Calculate the lattice energy in kJ/mol for CaCl2 from the following information: Energy needed to vaporize one mole of Ca(s) is 192kJ. For calcium the first ionization energy is 589.5kJ/mol and the second ionization energy is 1146kJ/mol. The electron affi...

4 years ago

How much energy, in joules, is required to break the bond in ONE chlorine molecule? The bond energy of Cl2 is 242.6kJ/mol?

4 years ago

Aluminum and Fluorine form a substance with the formula AlF3. Is the bond between Al and F polar? If so which atom carries the partial positive charge?

4 years ago

What kids of intermolecular forces must be overcome as CO2 sublimes? (check all that apply) 1. dispersion forces 2. dipole dipole 3. H-bonds 4. ion dipole

4 years ago

How many valence electrons does each of the following species contain? BN = HF = OH[1-] = CN[1-] =

4 years ago

Which of the following electron dot structures would have a charge of +2 and 1 valence electron? a) Mg2+ b) B2+ c) Al2+ d) Na2+

4 years ago

Identify the intermolecular force, or forces that predominate in Al2O3 (check all that apply) Group of answer choices 1. ionic 2. H-bonding 3. dispersion 4. dipole dipole

4 years ago

Which of the following compounds experience the strongest dipole-dipole attractions? a) CF4 b) CCl4 c) CF2Cl2

4 years ago

1) What are the bond angles in the molecular model of SI6? 2) What is the bond angle in the following molecular model of H2Te? 3) What is the geometry around the central atom in the following molecular model of BF3?

4 years ago

Which of the following molecules does not have a dipole moment? 1) CBr2=CBr2 2) NCl3 3) CH3NH2 4) HCl

4 years ago

Which of the following exhibits ion-dipole forces? 1) KBr(s) 2) NaF(aq) 3) Ag(s) 4) Cl2(g)

4 years ago

What is the hybridization of Chlorine in ClO3-? a) sp b) sp2 c) sp3 d) s

4 years ago

Which of the following should have the largest dipole moment? a) F2(g) b) SO2(g) c) RbBr(g) d) CH2I2(g)

4 years ago

The orbital hybridization on the carbon atom in S CN - is a) sp. b) sp2. c) sp3. d) sp3d2.

4 years ago

Which of the following is not true? a) The sp3 hybrid orbitals are degenerate. b) An sp3 hybrid orbital may hold a lone pair of electrons. c) An sp3 hybrid orbital may form a sigma bond by overlap with an orbital on another atom. d) An sp3 hybrid orbital...

4 years ago

Which of the following statements about cycloalkanes is true? 1) The bonds in cyclopropane and cyclobutane are weaker than other cycloalkanes. 2) Most cycloalkanes are planar molecules. 3) Cyclopropane has 109° bond angles. 4) Cycloalkanes are also called...

4 years ago

Which one of the following molecules is the most polar? 1) acetic acid 2) acetaldehyde 3) ethylene 4) ethane

4 years ago

How many grams of Ca(OH)2 are needed to neutralize 5.00 g of 3-methylbutanoic acid? a) 4.20 g b) 2.10 g c) 3.63 g d) 1.81 g

4 years ago

Which statement below is false concerning nomenclature rules for alkanes? 1) The name of the alkane is written as a single word. 2) Carbon atoms are numbered starting with the atom farthest from the branching point. 3) The parent name is taken from the lo...

4 years ago

Which name is NOT correct? a) 2, 3-dimethyloctane b) 2, 6, 6-trimethylheptane c) 2, 3, 3-trimethyloctane d) 2, 2-dimethylbutane

4 years ago

Question: Which one of the following molecules can rotate freely around its carbon-carbon bond? a) pentane b) cyclopropane c) benzene d) ethene Answer: My classmates saw the answer is pentane, is this correct?

4 years ago

@drbob222 The way I did it was 27.8/47.8 = 58.2 with 47.8g being the total weight of the first two chemicals

5 years ago

@DrBob222 How did you get C1 H2 O1? If 5.048g of the substance goes through combustion and produces 7.406g of CO2 and water shouldn't there be 3 oxygens?

5 years ago

My professor said to only keep 3 sig digs

5 years ago

I got 1180285267 or 1.18 x 10^9 Is this correct?

4 years ago

So for dE I got 4.0875 × 10-19 joules Over (6.62607004 × 10-34 m2 kg / s)(299 792 458 m / s) Do I have to then covert into nm?

4 years ago

@DrBob22 I think the question is asking how many valence electrons do each of the compounds have when they're together here are the answers I got: BN = boron has 3 valence electrons, nitrogen has 5, so together they have 8 HF= 1 for hydrogen, 7 for Flouri...

4 years ago

Which of the following exhibits ion-dipole forces? 1) KBr(s) 2) NaF(aq) 3) Ag(s) 4) Cl2(g)

4 years ago

I did google the question, I only ask the question on here to double check. I get a lot of conflictory answers on Google.

4 years ago

I think it is 2) because I know 1) and 3) are correct

4 years ago