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What is the mix ratio for shielding gas used in MIG welding steel?

A) 100% oxygen
B) 100% nitrogen
C) 75% argon, 25% CO2
D) 100% helium

1 Answer

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Final answer:

The correct mix ratio for MIG welding steel is 75% argon and 25% CO2. To determine the empirical formula of acetylene, calculate the moles of carbon and hydrogen from percentages given and derive the simplest whole-number mole ratio. Then, apply the Ideal Gas Law to find the molecular formula from the gaseous state conditions provided.

Step-by-step explanation:

The mix ratio for shielding gas used in MIG (Metal Inert Gas) welding steel is typically C) 75% argon, 25% CO2. This blend provides a good balance of properties to protect the weld area from oxygen and nitrogen in the air, which can cause weld defects.

Now, to find the empirical formula for acetylene, a fuel used in welding torches, we use its composition by mass. For 92.3% carbon (C) and 7.7% hydrogen (H), we assume 100 grams of acetylene and convert these percentages to grams. We then convert grams to moles for both carbon (by dividing by its molar mass, 12.01 g/mol) and hydrogen (by dividing by its molar mass, 1.008 g/mol). The empirical formula is determined by finding the simplest whole-number ratio of these moles.

To find the molecular formula of acetylene, we use the given conditions and apply the Ideal Gas Law (PV = nRT) to find the number of moles of acetylene in 1.10 g. From there, we compare the mole calculated to the empirical formula weight to determine the actual molecular formula.

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