(Incorrect) An impure sample of hydrocarbon having a total mass of 41.0 g undergoes combustion analysis to generate 82.6 g CO₂(g) and 16.9 g H₂O(g). Assuming that the impurities do not contain carbon or hydrogen, what percentage of the initial sample is the pure hydrocarbon? Provide the numerical value of your response in decimal notation rounded to 3 significant figures. You answered: 4.58 The correct answer is: 59.5%

A student finds that they have 0.2545 g of NH4Cl, 1.1502 g of NaCl, and 1.0181 g of SiO2. Calculate the percent gained or lost during this experiment if the initial mass of the mixture was 2.5537 g.

Calculate the following to the proper significant figures:  The molecular mass of iron(II) hydroxide.  The number of moles in 145g of MgCl2 The volume of 25.0g of steam at STP(steam is gaseous water)  The concentration of a solution of table salt (NaCl) if 12g is dissolved in 1.5L of water

Aqueous hydrobromic acid  HBr  reacts with solid sodium hydroxide  NaOH  to produce aqueous sodium bromide  NaBr  and liquid water  H2O . If  0.321g  of water is produced from the reaction of  3.2g  of hydrobromic acid and  2.1g  of sodium hydroxide, calculate the percent yield of water.Be sure your answer has the correct number of significant digits in it.

What is the numerical value of Avogadro's number? Report your answer to 4 significant figures. (Your answer should be entered as in the following example: 1000 = 1.0E+3.)

A student sets up the following equation to solve a problem in solution stoichiometry. (The ? stands for a number the student is going to calculate.) Enter the units of the student's answer. (0.19 L) 1 mL 10-³ 146.86 g mol 1.04 mL = ☐ x10 ロ･ロ X I 00

11195@djis.edu.sa Switch account Your email will be recorded when you submit this form * Required Choose the correct answer: Using the following equation: Fe:O:(s) + 3H2(g) → 2Fe(s) + 3H2O(1) How many grams of iron,Fe, can be made from 6 g H2? MM (H2) = 2g/mol and MM (Fe) = 56 %3D g/mol * 56 g 112 g O 168 g O 12 g

When answering this problem, report the answer with the appropriate number of significant figures. Enter your answer USING scientific notation. When entering units, use proper abbreviated units with proper capitalization. In this experiment, a series of solutions are prepared by combining multiple components into a single container. One solution prepared contains 5.00 mL of 0.010 molar KI, 10.00 mL of 0.0010 molar Na2S2O3, 15.00 mL of water, 10.00 mL of 0.040 molar KBrO3, and 10.00 mL of 0.10 molar HCl.  What is the concentration of iodide ions in this solution? Answer: ____x10______units

A chemist invents a new combustion analysis instrument that uses less O2(g) which saves money on each analysis. The improvement is that instead of CO2(g) being formed and trapped, CO(g) is formed and trapped. H2O (g) is also formed and trapped when substances that contain hydrogen are analyzed.(a) The chemist places 2.184 g of an unknown compound of carbon and hydrogen in the new analyzer. 4.627 g of CO (g) and 1.795 g of H2O (g) are produced. Find the empirical formula for the compound.(Molar masses (g/mol): CO = 28.0104, H2O = 18.015) (b) Despite the best efforts of the chemist, the molar mass of the compound cannot be determined (using this method). Clearly explain why this prevents the determination of the molecular formula

Gaseous ethane CH3CH3 reacts with gaseous oxygen gas O2 to produce gaseous carbon dioxide CO2 and gaseous water H2O. What is the theoretical yield of water formed from the reaction of 2.10g of ethane and 15.1g of oxygen gas? Be sure your answer has the correct number of significant digits in it. I keep getting this problem wrong because of the sig. digits, dont round till the end because if it is off by 0.1, it will be incorrect.