laboratory procedure calls for making 510.0 mL of a 1.3 MKNO3 solution. How much KNO3 in grams is needed? Express your answer using two significant figures.

How many moles of sodium hydroxide, NaOH, are present in 1.73 L of a 0.157 M sodium hydroxide solution? Place your answer in the box. Express your answer using only a number without text. Report your result in decimal notation and to the proper number of significant figures. All numbers are measured.

A chemistry student must write down in her lab notebook the concentration of a solution of sodium hydroxide. The concentration of a solution equals the mass of what's dissolved divided by the total volume of the solution. Here's how the student prepared the solution: • The label on the graduated cylinder says: empty weight: 8.200 g • She put some solid sodium hydroxide into the graduated cylinder and weighed it. With the sodium hydroxide added, the cylinder weighed 45.74 g- • She added water to the graduated cylinder and dissolved the sodium hydroxide completely. Then she read the total volume of the solution from the markings on the graduated cylinder. The total volume of the solution was 24.09 ml. What concentration should the student write down in her lab notebook? Be sure your answer has the correct number of significant digits. ml

The composition of a mixture of potassium chlorate and potassium chloride is to be determined. A 9.5 gram sample of the mixture is heated until the creation of oxygen gas stops. If the sample mass after heating is 7.44 grams, what is the percent by mass of potassium chlorate in the mixture? Report your answer with 3 significant figures.