Air is a mixture of several gases, where the two most dominant components in dry air are 21 vol% oxygen and 78 vol% nitrogen. Oxygen has a molar mass of 15.9994 g/mol and nitrogen has a molar mass of 14.0067 g/mol In English units, the standard unit of measurement of molecular mass of air is 'lbm/lbmol' (pound - mass/pound - mole). The actual value of molar mass of air remains the same as the fractions of its constituents which are taken into consideration for the calculations. Hence, the molar mass of air, in English units, is 28.96 lbm/lbmol ** Add all the molecular weight fractions to arrive at a molar mass of air of 28**.9656. What this number means is that one mole or one molecular measure of air that contains 6.0221367 X e^23 molecules of gas weighs 28.9656 grams at standard atmospheric conditions of 60 degrees Fahrenheit and 14.696 pounds-per-square-inch absolute (psia) The molar mass of dry air is 28.9647 g/mol. Composition and content of each gas in air is given in the figures and the table below Molar mass of dry air, 0.0289652 kg/mol Molar mass of water vapor, 0.018016 kg/mol Universal gas constant, 8.31446 J/ (K·mol) The vapor pressure of water may be calculated from the saturation vapor pressure and relative humidity

Argon: (0.934 / 100) x 39.948 = 0.373 g/mol Carbon dioxide: (0.03 / 100) x 44.01 = 0.013203 g/mol If we add these up we get: 21.8739 + 6.7025 + 0.373 + 0.013203 = 28.96 g / mol The average molar mass of the air concept was stated in1. The air is not a chemical compound. The air is a mixture of molecules of chemical elements like nitrogen N 2 and oxygenO 2 andofchemicalcompoundslikecarbondioxideCO 2,watervaporH 2O,andeven of atoms of chemical elements like helium He and other gases. Taking into account onl As an example, the average molar mass of dry air is 28.97 g/mol. Related quantities. Molar mass is closely related to the relative molar mass (M r) of a compound, to the older term formula weight (F.W.), and to the standard atomic masses of its constituent elements The Molar Mass of Dry Air is 0.0289644 kilograms per mole (kg/mol). Use the pull-down menu to automatically convert kg/mol to compatible units. Related Calculators. Barometric Pressure for the upper atmosphere (Troposphere) Standard Temperature at Sea Level; Standard Atmospheric Pressure at Sea Level ; Temperature Lapse Rate for Dry Air

* Molecular weights of common gases Including molecular mass of air, ammonia, natural gas, water vapor*. Question or remark ? Please contact us at powder.process@protonmail.co The molar mass of nitrogen (N 2) and oxygen (O 2) are 28.014 g mol −1 and 31.998 g mol −1 respectively. Therefore, the molar of air is 28 g mol −1. Example 4: To Determine Molar Mass of Sodium Chloride Solution Sodium chloride a common salt The total pseudo-mass is 28.84, which is the average molar mass of air with the stated composition. Divide the individual pseudo-masses by 28.84 to arrive at 0.233 weight fraction oxygen and 0.767 weight fraction nitrogen

The average molar mass of the air will equal the contribution of each of the components (in this case, simplified to 80% N2 and 20% O2. Therefore, this equation should be used: Ave. Molar Mass of air = (.80 x 28g/mol) + (.20 x 32g/mol) Thank You very much, I think with all the help from the contributers of this site I am actually looking foward to Chem 2..lol . Log in or register to post. The molecular weight of air is approximately 28.97 g/mol. The molecular mass is estimated using the weights of all of the elements contained in air Molar mass of dry air in mass metrology 1. Introduction. In metrology, an unknown mass is determined from a set of comparisons with a standard carried out in... 2. Density of moist air. The procedure, recommended by the Comité International des Poids et Mesures, is to calculate... 3. Molar mass of.

Humid air is treated as a binary mixture of two real gases, dry air and water vapour. The composition of dry atmospheric air is assumed to be that given by Harrison (1965). Harrison's value of the molecular mass of dry air, Ma= 28.9645 g/mol,is used throughout the equations. The molecular mass of water is taken as Mw= 18.016 g/mol The molar mass of air is 28.9628 g/mol. Here's how we arrive at this answer. Calculating the molar mass of air requires knowledge of the percent... See full answer below

Calculate the molar mass of air: Molar mass is a physical property defined as the mass of a given substance divided by its amount of substance, so it is a weight of one mole of substance. Molar mass is defined from the ideal gas law (Equation Mendeleev-Clapeyron) Since 1980, the different national metrology institutes use the same procedure and formula for **air** density determination. The formula employed assumes some hypotheses on the composition of dry **air** and is expressed in terms of its **molar** **mass** and the four environmental parameters: **air** pressure, **air** temperature and concentrations of carbon dioxide and water vapour. In this formula (known as CIPM-1981/91) recommended by the Comité International des Poids et Mesures, the mole fraction of argon. Water is composed of a hydrogen atom and two oxygen atoms (H 2 O) and has a molecular weight of 18 grams per mole. (One mole of a gas, at standard conditions, has a volume of 22.4 liters.) Dry air contains no water vapor, and is mostly a mixture of molecular nitrogen (N 2) and molecular oxygen (O 2) Since the 1956 Model Atmosphere of the Air Research and Development Command employs a variable scale height gradient with altitude, the diffusive equilibrium and mixing formulas of Nicolet and Mange were modified to obtain the vertical distributions of the various atmospheric constituents

Then your sample consists of 98% dry air molecules (average molar mass 29) and 2% water molecules (molar mass 18). The molar mass of the combined sample is: 29 g / m o l × 0.98 + 18 g / m o l × 0.02 = 28.78 g / m o l. Share By volume, the earth's atmosphere contains: Molecular weight of N 2 is 2*14.0067 g/mol, 78.084% of air Molecular weight of O 2 is 2*15.9994 g/mol, 20.946% of air Molecular weight of Ar is 39.948 g/mol, 0.9340% of air The molecular weight Ma of moist air is given by where Ma,dry =28.96x10-3 kg mol-1 is the molecular weight of dry air derived in (1.10), and MH2O = 18x10-3 kg mol-1. For CH2O = 0.03 mol/mol we obtain Ma = 28.63x10-3 kg mol-1. A mole of moist air is lighter than a mole of dry air Calculates average molecular weight using a mass basis and a molar basis. Made by faculty at the University of Colorado Boulder Department of Chemical and Bi..

* The dry ambient air outside the tube is at 1 atm (101*.3 kPa) and 298 K. Water evaporates and diffuses through the air in the tube, (molecular weight 159.63) and 5 mole of hydration water diffuse through the liquid film from the surface of the crystal to the bulk of the liquid phase. Let A = CuSO 4 and B = H 2O then, NB = 5 NA The molar flux of A is NA,z = − cD AB A dx dz + xA(NA,z + NB,z. Air is a mixture of several gases, where the two most dominant components in dry air are 21 vol% oxygen and 78 vol% nitrogen, Argon: 0.934% and Carbon dioxide: 0.03%. Since both of these elements are diatomic in air - O 2 and N 2, the molar mass of gases are given by The atomic / molecular weights are

How to Calculate Molar Mass - YouTube The molecular weight of air is approximately 28.97 g/mol. The molecular mass is estimated using the weights of all of the elements contained in air. Air is mostly made of oxygen and nitrogen. Dry air also contains the following components: carbon dioxide, argon, helium, hydrogen, krypton and xenon. Based on the molecular weights of each of these components and their respective ratios in air.

air molecular weight. Extended Keyboard; Upload; Examples; Random; Compute answers using Wolfram's breakthrough technology & knowledgebase, relied on by millions of students & professionals. For math, science, nutrition, history, geography, engineering, mathematics, linguistics, sports, finance, music Wolfram|Alpha brings expert-level knowledge and capabilities to the broadest possible. Air is composed of 75.54% nitrogen, 23.10% oxygen, and 1.3% argon by mass. The mean molar mass is therefore m_{\rm air} = 29.0 {\rm\ g\ mol}^{-1}, and air can be taken as a single diatomic gas with molar mass 29.0 g to a good degree of approximation. At standard temperature and pressure, the speed of sound is 331.1 m s-1, and increases by roughly 0.61 m s-1 for each degree celsius above 0. Processing.... Molecular weights of common gases Including molecular mass of air, ammonia, natural gas, water vapor. Follow us on Twitter Question, remark ? Contact us at contact@myengineeringtools.co Air can be treated for most purposes as an ideal gas. The following equations are all of good engineering accuracy over the relevant range. The relative molecular mass (molecular weight) of dry air is M A ¼ 28:965 with a corresponding molar mass m A ¼ 28:965kg=kmol The speciﬁc gas constant is R A ¼ 287:05J=kgK The absolute (kelvin.

- The molecular weight of air in terms of kg and kmol is then air 28.97 g 1000 mol kg kg 28.97 mol kmol 1000 g kmol M . In English units, the pound-mass (lbm) is the standard unit of mass. In order to use the same molecular weights as those listed on the periodic chart, the pound-mol, (lbmol, sometimes lb-mol, lbm-mol, or lbm-mole) is defined. The molecular weight of elemental (atomic) nitrogen.
- What are approximate mole and mass ratios of N2 and O2 for air? Approximate Air: 0.21 02 + 0.79 N2 (mole basis) 0.79 / 0.21 = 3.76 = N2/O2 mole rati
- Molecular Weight (kg/kmol) Dry Air 286.9 28.97 Water vapor 455 18.02 . Pressure in Moist Air - Daltons Law Daltons Law for moist air can be expressed as: p = p a + p w (1) where p = total pressure of air (Pa) p a = partial pressure dry air (Pa) p w = partial pressure water vapor (Pa) The maximum pressure possible before vapor start to condensate at an actual temperature is called the.

- es the molecular mass of a substance. Enter the molecular formula of the substance. It will calculate the total mass along with the elemental composition and mass of each element in the compound. Use uppercase for the first character in the element and lowercase for the second character. Examples: Fe, Au, Co, Br, C, O, N, F. You can use parenthesis or brackets []. Finding.
- Multiply the % of each element by the molar masses to get the mass that each element contributes to air. 78.08% N x 28g/mol, 20.95% O x 32 g/mol, and 0.97% x 39.95 g/mol Ar will give you 21.85 g N2, 6.70 g O2, and 0.38 g Ar added together gives you 28.94 g/mo
- IMBSIR77-1278 FILEcopy I DONOTREMCE I _ i TheAirDensityEquationand theTransferoftheMassUnit FrankE.Jones InstituteforBasicStandards NationalBureauofStandards Washington,D.C.20234 July1977 U.S.DEPARTMENTOFCOMMERCE NATIONALBUREAUOFSTANDARDS Wt£Mo'HBM
- Calculate the mass of oxygen (in mg) dissolved in a 5.00 L bucket of water exposed to a pressure of 1.13 atm of air. Assume the mole fraction of oxygen in air to be 0.21 and the Henry's law constant for oxygen in water at this . chemistry. air has an average molar mass of 29.o g/mol. The density of air at 0.97 atm and 30. C i

Speed of Sound (air, ideal gases) - relative to molar mass Solve. Add to Solver. Description. The speed of sound is the distance travelled per unit time by a sound wave propagating through an elastic medium. The SI unit of the speed of sound is the metre per second (m/s). In dry air at 20 °C, the speed of sound is 343.2 metres per second (1,126 ft/s). This is 1,236 kilometres per hour (768. The molar mass of dry air depends on its composition but for so called standard air is it M da= 0:028964 kg/mol, for which in calculations we often use an approximation M da ˇ0:0290 kg/mol. The molar mass of water apvor (and water) is M v = 0:0180153 kg/mol, for which the approximation used in calculations is M vˇ0:0180 kg/mol. According to the ideal gas law, the partial density of dry air. ›› air molecular weight. Error: air is unknown. Try another chemical formula, or view the list of known compounds. Note that all formulas are case-sensitive. ›› Calculate the molecular weight of a chemical compound. Enter a chemical formula: Browse the list of common chemical compounds. ›› More information on molar mass and molecular weight. In chemistry, the formula weight is a. Molecular Weight of Air Introduction The air we breathe, the carbon dioxide pumped into our soda cans, and the hydrogen balloons that science instructors fondly explode during class are each examples of gasses. The physical behavior of gases can be described by scientific laws that are grounded in hundreds of years of experimentation. This week, we will perform hands-on scientific inquiry.

- Nitrogen has a molecular weight of 14 so a N 2 molecule has a molecular weight of 28. Oxygen has a molecular weight of 16 so an O 2 molecule has a molecular weight of 32. Given the mixture of gases found in
**air**the average molecular weight of**air**is around 29. Water is made up of two hydrogen and one oxygen atoms (H 2 O). Hydrogen is the lightest element and has a molecular weight of one. So a. - Convert a unit for air pollution into another. This is a converter for units used in the field of air pollution. Usage: At first choose the pollutant from the pull-down-menu. You may choose O 3, NO 2, NO, SO 2, CO, CO 2, or H 2 O. For another substance (?) you have to type its molar mass
- Total molar mass of the combustion products as a gas mixture: MolarMass(mixture) = [tex]\Sigma[/tex]f j MolarMass j = 30.3972 g/mol Is the second method the correct approach, or am I totally missing the point? Answers and Replies Apr 2, 2010 #2 Borek. Mentor. 28,674 3,166. I have troubles understanding what the second method is for. When you mix gases you can assume (with a good approximation.
- This report describes a method for obtaining the so‐called molecular weight of air at high altitudes of the earth's atmosphere above the transition region for the dissociation of molecular into atomic oxygen. A reasonable working model, based upon the ratio of absolute temperature to molecular weight T/M, which is proportional to the slope of the log e pressure υs altitude curve, is.
- molar mass of dry air should be viewed with proper perspective. The total contribution of the trace gases to M da is 0.0006. Readers may not agree with adding the 2.9 µmol ⋅mol-1 to the trace.
- Molecular mass (molecular weight) is the mass of one molecule of a substance and is expressed in the unified atomic mass units (u). (1 u is equal to 1/12 the mass of one atom of carbon-12) Molar mass (molar weight) is the mass of one mole of a substance and is expressed in g/mol. Weights of atoms and isotopes are from NIST article. Give us.
- Calculate the molar mass and density of dry air at 0 °C and 1.0 atm. Assume ideal behavior and use two significant figures in your answers. CHEM. Air is approximately 80% nitrogen and 20% oxygen (on a mole basis). If 6 g of hydrogen is added to a 22.4 liter maintained at 0 degrees c and initially filled with air at 1 atm pressure, what will be the molecular mass (i.e. the . Chemistry. The.

Determine the identity of the gas by comparing the calculated molar mass to molar masses of known gases. Solution: A Since we are at STP, we can use the following equation to calculate molar mass: \[MM = \rho \cdot 22.4 L/mol\] \[MM = \rm 1.783 g/L \cdot 22.4 L/mol\] \[MM = \rm 39.9 g/mol\] B The calculated molar mass is 33.9 g/mol. Examination of the periodic table reveals that Argon has a. * Solution for What is the molar mass of air, measured at 25 ̊C, 770 mm Hg? The density of the air under these conditions is 1*.20 g/L Molecular weight Density - ρ-kg/m 3lb m /ft3 Formula Density - ρ 3 /ft3 1) NTP - Normal Temperature and Pressure - is defined as air at 20 oC (293.15 K, 68 F) and 1 atm ( 101.325 kN/m2, 101.325 kPa, 14.7 psia, 0 psig, 30 in Hg, 760 torr) 2) STP - Standard Temperature and Pressure - is defined as air a S = M / M air, where S=gas specific gravity, M=gas molecular weight, M air =28.96443 g/mole (molecular weight of standard air - CRC, 1983). The gas specific gravity calculation does not check for unreasonable inputs. Please enter positive values. Equations for Ideal Gas Law Calculator (CRC, 1983) R u = 8.3144126 N-m/mole-K . The ideal gas law calculation internally converts all user inputs to.

- g the molar mass equals that of dry air. (e) The lifting capacity of a hot air balloon is equal to the difference in the mass of the cool air displaced by the balloon and the mass of the gas in the balloon. What is the difference in the mass of 1.00 L of the cool air in part (c) and the hot air in part (d)? (f) An average balloon has a diameter of 60 feet and a.
- The molar mass of dry air is calculated as the sum of the products of the mole ratio of each gas times its molar mass. In the last half of the twentieth century, the following changes took place that resulted in an increase in the molar mass of dry air: * The scientific community changed from the Oxygen-16 to the Carbon-12 reference for the molar mass of elements and compounds in 1960. * The.
- e the mass fraction of both oxygen and nitrogen and the mean molecular weight of the air when it is maintained at 25 C (298 K) and 1 ATM . The molecular weight of oxygen is 0.032 kg/mol and of nitrogen is 0.028 kg/mol
- Molar Mass of Gases and Gas Mixtures. Molar mass (M) is equal to the mass of one mole of a particular element or compound; as such, molar masses are expressed in units of grams per mole (g mol -1) and are often referred to as molecular weights.The molar mass of a particular gas is therefore equal to the mass of a single particle of that gas multiplied by Avogadro's number (6.02 x 10 23)

Molar mass is measured in g/mol and molecular mass is measured in Daltons (Da). The molar mass of a substance is not really an indication of the properties of individual molecules Individual molecules of a substance can differ in weight due to the presence of different isotopes of elements. The molar mass of water might be 18.02 g/mol, but this does not mean that each molecule of water weighs. Carbon dioxide gas (CO2) has a molar mass of 44 g/mol. The two major components of air, which are oxygen and nitrogen, have molar masses of 32 g/mol and 28 g/mol, respectively. Calculate the room-temperature densities in g/L of nitrogen (N2), oxygen (O2), and carbon dioxide (CO2) gases. 1 See answer paigefowler2273 is waiting for your help. Add your answer and earn points. mymonkey123456.

* This paper provides a brief history of the molar mass of dry air, Mda, followed by the composition of Earth's atmosphere for the year 2008 and the calculation of M da*. A single equation is given to calculate Mda based on the actual abundance of CO 2 in the atmosphere, which is currently increasing at an annual rate of 1.9 ìmol·mol −1 Simulation - Apparent Molecular Weight of Air Name: Lab TA: Mon Tue(am) Tue(pm) Wed Thu(am) Thu(pm) Fri Lab Day Grade >95 >90 >85 >80 >70 <70 Report: Report Submitted on Time (Check Box) Yes No . Some Useful Values You May Need: R (The Ideal Gas Constant): 0.08205 L.atm.mol-1. K-1. Convert . 0. C to K: 0 . 0. C + 273.15 = 273.15 K. Data Collection: Exp 6a: Study the Relationship Between. 4.2: Molar Mass Last updated; Save as PDF Page ID 79550; Contributor; As we described in Section 4.1, in chemistry, the term mole can be used to describe a particular number. The number of things in a mole is large, very large (6.0221415 x 10 23).We are all familiar with common copy-machine paper that comes in 500 sheet reams

Air. Formula--Molecular Weight (lb/mol) 28.96: Critical Temp. (°F) N/A: Critical Pressure (psia) N/A: Boiling Point (°F) -317.8: Melting Point (°F) N/A: Psat @ 70°F (psia) (note 1) Liquid Density @ 70°F (lb/ft³) (note 1) Gas Density @ 70°F 1 atm (lb/ft³) 0.075: Specific Volume @ 70°F 1 atm (ft³/lb) 13.3: Specific Gravity: 1.000: Specific Heat @ 70°F (Btu/lbmol-°F) 6.96: Notes. The molar mass, and thus density, of helium, is much less than that of air, which is primarily nitrogen and oxygen. Also, notice that density and temperature are inversely related. This is observed when piloting a hot air balloon. Turning on the burner heats up the air molecules within the balloon and they move faster. The pressure in the balloon increases, but the balloon is designed so that.

Answer to: Air has an average molar mass of 29.0 g/mol. Find the density of air at 0.97 atm and 30 degree C. By signing up, you'll get thousands of.. Molar Mass - Formula. It is all very well to calculate the atomic molecular and formula masses of atoms, molecules, and other compounds, but since we cannot weigh an individual particle, these masses have a limited usefulness.To make measurements of mass useful we must express chemical quantities at the macroscopic level Hence Molar mass of H2 = 1.008 x 2 = 2.016 Substituting the values in the formula, = [ ( 3.2 / 2.016 ) / ( 1.8 / 28.013 ) ] = [ 1.5873 / 0.064255 ] = 24.703 Hence the molar ratio is 1 : 24.703. Related Calculators: Periodic Table ; Acids And Bases ; Neutralisation ; Henderson Calculator ; Molecular Weight Calculator ; Air Duct Calculator ; Height Of A Scalene Triangle Calculator ; Calculators.

Question: The Average Molar Mass Of Air Is 28.8 G/mol. On A Winter Daythe Average Atmospheric Pressure Is 650 Torr And The Temperature Is-250C. What Is The Molar Density(in Mol/L) Of Air Underthese Conditions?Im Having A Bit Of Trouble Setting This Question. I Know Its Amol To Mol Calculation Im Just Having Trouble. Thanks Inadvance Überprüfen Sie die Übersetzungen von 'molair' ins Deutsch. Schauen Sie sich Beispiele für molair-Übersetzungen in Sätzen an, hören Sie sich die Aussprache an und lernen Sie die Grammatik Super-Angebote für Mass Air hier im Preisvergleich bei Preis.de You can take advantage of the fact that one mole of any ideal gas occupies 22.4 liters at STP, then use the ideal gas law (preferably with real gas corrections, but that would require assumptions about the average molar mass of air-- if you do cho..

- The accepted value for air at 28.97 g/mol makes sense because .78 of the mol is Nitrogen and .21 of the mol is Oxygen. 21% of the molar mass of O 2 is about 6.7 g, and 78% of the molar mass of N 2 is about 21.8 g. When adding those two values together, you get 28.5 g, which is extremely close to the accepted value of the molecular weight of air, 28.97 g. The obtained value of the molecular.
- Homework Statement How many moles of MgIn2S4 can be made from one gram each of Mg, In, and S? Atomic masses are given. Homework Equations Moles = mass/molecular mass The Attempt at a Solution I have found the moles of each entity. Mg - 0.04167 moles In - 0.00871 moles S -..
- Bookmarks: [ weight to volume | volume to weight | price | density ] A few materials, substances, compounds or elements with a name containing, like or similar to air: acid of air [CH 2 O 3] weighs 2 540 kg/m³ (158.56702 lb/ft³) [ weight to volume | volume to weight | price | mole to volume and weight | mass and molar concentration | density
- We performed an in-depth study of high molecular weight poly[3,6-(dithiophene-2-yl)-2,5-di(2-octyldodecyl)-pyrrolo[3,4-c]pyrrole-1,4-dione-alt-thieno[3,2-b]thiophene] P(DPP2OD-TT) synthesized through the Stille coupling polycondensation in order to understand the correlation between molecular weight, processing conditions and charge transport.We observed a rapid increase in its aggregation in.
- If the air mass is measured in grams, then the calculated amount of fuel will also be in grams. Using an average density of gasoline of 6.17 pounds per gallon and knowing that there are 454 grams per pound, then dividing the total fuel mass in grams by (454 * 6.17) yields the total number of gallons of fuel burned for a given amount of air (as measured by the MAF sensor)
- Molecular Weight Search Help Search options (step 1) (Back to search) You may search for species based on molecular weight values in two ways: Specify a single value; the system will search for values within 0.5 units of this value. Specify a range. The limits of the range should be separated by a comma

Molecular diffusion, often simply called diffusion, is the thermal motion of all (liquid or gas) particles at temperatures above absolute zero.The rate of this movement is a function of temperature, viscosity of the fluid and the size (mass) of the particles. Diffusion explains the net flux of molecules from a region of higher concentration to one of lower concentration Molecular weight is indirectly proportional to the rate of diffusion: the smaller, lighter particles disperse faster compared to larger, heavier particles. On average, a particle moves at around 3,997 miles per hour at room temperature. Diffusion refers to the net arbitrary motion of particles from areas of higher concentration to areas of lower concentration until the concentration gradient. Par conséquent, la masse molaire d'une substance telle que l'air dépend de la somme de toutes les fractions volumiques de chaque composant moléculaire multipliées par leur poids moléculaire individuel. Déterminez les principaux éléments gazeux qui composent l'air et leurs fractions volumétriques moyennes comprenant l'air (où l'air équivaut à 1 unité volumétrique). Par ordre. Since air is made up predominantly of nitrogen gas, the molecular weight of air is very close to that of nitrogen, i.e. In S.I. units, the kilogram (kg) is preferred over the gram; thus the kilogram-mol (kmol, sometimes kg-mol or kg-mole) is often used instead of the mol. By definition, a kmol is defined as 1000 mol, or 6.0251 x 10 26 molecules of the substance. The molecular weight of air in. Molar mass refers to the weight of one mole of a substance, which is similar to atomic mass but is often thought to be more universally precise. A mole is the amount of a substance that contains the same number of elemental entities, such as electrons, ions, and atoms, as there are in 12 grams of carbon -12