(ii) A sample of 3.25 cm³ of bromine vapour leaks into a laboratory. Calculate the minimum volume, in dm³, of the laboratory for the resulting concentration of bromine to be at a safe level.

Write the formula for a micelle of a sol of barium sulfate, obtained by the exchange reaction between barium nitrate and potassium sulfate in the case of an excess of barium nitrate.

A volume of 125.0 mL of 0.565 M KOH (aq) is diluted with 425.0 mL of pure water.  What is the final concentration (in molarity) of KOH? Report to three significant figures.

When treating a mixture of metals( copper and zinc) with an excess of solution of hydrochloric acid, 2.24 liters of a gas(STP) were released.   When the same mixture was treated with phosphoric acid precipitate of 93.5g is formed.  Find the mass fraction of metals in the initial mixture.

Complete and balance each of the following equations for gas-evolution reactions. (NH4)2SO4(aq)+Ca(OH)2(aq)→ Express your answer as a chemical equation. Identify all of the phases in your answer. I tried to do the equation, but it says it's wrong.

A 12.63 g sample of calcium ore was dissolved in HCl and gravimetrically analyzed, through the precipitation of calcium into CaC2O4 · H2O. The precipitate was filtered, washed, dried, and ignited at 500 oC until the weight was constant, giving a final mass of 2.35 grams pure CaCO3 (100.087 g/mol). Calculate the % Calcium (40.078 g/mol) in the sample.

A lump of sucrose of mass 10.0 g is suspended in the middle of a spherical flask of water of radius 10 cm at 25 °C. What is the concentration of sucrose at the wall of the flask after (a) 1.0 h, (b) 1.0 week. Take D = 5.22 × 10−10 m2 s−1.

The aluminum in a 1.200 g sample of impure ammonium aluminum sulfate was precipitated with aqueous ammonia as the hydrous Al(OH)3.xH2O. The precipitate was filtered and ignited at 10000C to give anhydrous Al2O3 which weighed 0.1798 g. Express the result of this analysis in terms of % Al2O3.

A chemical reaction occurred when 500 mL of 7.5 x 104M Cal2 and 100 mL of 1.7 x 105M Pb(NO3)2 solutions were mixed at 25.0°C. Ksp = 1.4 x 108 а. Write out the complete chemical reaction that occurs when the calcium iodide is mixed with lead(II)nitrate. The equation must be balanced, and the states of matter need to be shown. b. Determine whether a precipitate will form. If the temperature at which the substances were mixed was lowered to -25.0°C, do you С. think that could impact your answer given in part b? Explain your answer using your knowledge about equilibrium. Assume the volumes and concentrations were not impacted by the temperature change.

About 6x 10°g of goldis thought to be dissolved in the oceans of the world. If the total volume of the oceans is 1.5 x 1021 L, what is the average molar concentration of gold in seawater?