Andrea and her lab partner were conducting a variety of experiments to produce gases: hydrogen, oxygen, and carbon dioxide. In one experiment, they added a piece of magnesium ribbon to 10 milliliters of hydrochloric acid. They observed bubbles being produced and did a variety of tests to identify the escaping gas; it proved to be hydrogen. The reaction is represented by the following equation:
Mg + 2HCl → MgCl2 + H2(g)
If Andrea and her partner produced 0.250 mols H2, at STP, what is the mass of the hydrogen gas, in grams?

A) 0.253g
B) 0.505g
C) 2.183g
D) 4.044g

The organism shown is a free-living one that is anchored to the bottom of ponds and streams during one stage of its life cycle what is the common name for the group to which this organism belong

Maleic acid is a carbon-hydrogen-oxygen compound used in dyeing and finishing fabrics and as a preservative of oils and fats.* in a combustion analysis, a 1.054-g sample of maleic acid yields 1.599 g of co_2 and 0.327 g of h2o.* when 0.609 g of maleic acid is dissolved in 25.00 g of glacial acetic acid, the freezing point drops by 0.82 c. maleic acid does not ionize in glacial acetic acid, which has a freezing-point depression constant of k_{\rm f}=3.90~^\circ {\rm c}/m.* in a titration experiment, a 0.4250- g sample of maleic acid is dissolved in water and requires 34.03 ml of 0.2152 m koh for its complete neutralization.* the ph of 0.215 g of maleic acid in 50.00 ml of aqueous solution is found to be 1.80.part adetermine the empirical formula for maleic acid. enter the atoms in order ofc, h, and o. part bdetermine the molecular formula for maleic acid. enter the atoms in order of c, h, and o. express your answer as a chemical formula. part cbased on the titration data, how many ionizable h atoms are in each molecule of maleic acid, c4h4o4? express your answer as an integer. i got the part a and b which is cho and c4h4o4 respectively, can anyone me for part c? the below is what i have so far from other qa'sfinding the empirical formula for maleic acid, needs this info"a combustion analysis a 1.054-g sample of maleic acid yields 1.599g of and 0.327g of ".the rest of your data is used to find molar mass, molecular formula, equivalent mass, # of h+ ions / molecule & katypically this should be: a 1.054-g sample of maleic acid yields 1.599g of co2 and 0.327g of h2osofind mass using molar masses1.599g of co2 @ (12.01 g carbon) / (44.01 g co2) = 0.436 grams of carbon0.327g of h2o @ (2.016 g hydrogen) / (18.01 g/mol h2o) = 0.037 grams of hydrogen1.054-g sample - 0.436 grams of carbon - 0.037 grams of hydrogen = 0.581 grams of oxygennow use molar masses to find moles0.436 grams of carbon @ 12.01 g/mol = 0.0363 mol c0.037 grams of hydrogen @ 1.008 g/mol = 0.0367 mol h0.581 grams of oxygen @ 16.00 g/mol = 0.0363 mol oyour empirical formula ischo and molecular is c4h4o4

At a certain temperature the rate of this reaction is first order in hi with a rate constant of : 0.0632s2hig=h2g+i2g suppose a vessel contains hi at a concentration of 1.28m . calculate how long it takes for the concentration of hi to decrease to 17.0% of its initial value. you may assume no other reaction is important. round your answer to 2 significant digits.