Part B: Density of a Cylindrical Solid 1) Obtain a cylindrical solid and measure its mass. 2) Measure diameter and divide by 2 for the radius, and measure height. 3) Determine the volume by means of πr2h. 4) Determine the density and percent error. Part C: Density of an Irregular Shaped Solid 1) Obtain a sample of metal and determine the mass.
3 x (C H5 N) = C3H15N3 Hydrated compounds Solving process: 1st- the difference between the initial mass and that of the dry sample is the mass of water that was driven off. Mass of hydrate minus mass of dry sample equals the mass of water 10.407 – 9.520 = 0.887 g 2nd- The mass of dry BaI2 and the mass of water are converted to MOLES. 9.520 g BaI2 x 1 mol BaI2 ∕ 391 g BaI2 = 0.0243 mol BaI2 anhydrate 0.887 g H2O x 1 mol H2O / 18.0 g H2O = o.o493 mol H2O 3rd: Dividing both results by the amt of 0.0243 mol, we get a ratio of 1 to 2.03, or 1 to 2, since the formula must have full numerical integers of water molecules, in other words no fractions of a water molecule. Thus, for every 1 mole of BaI2, there are two moles of water. The formula for the hydrate is written as BaI2 • 2H2O And it is named barium iodide dihydrate.
25.0 cm3 of a 0.10 moldm-3 solution of sodium hydroxide was titrated against a solution of hydrochloric acid of unknown concentration. 27.3 cm3 of the acid was required. What was the concentration of the acid? 3. 25 cm3 of a solution of sodium hydroxide reacts with 15 cm3 of 0.1 mol/dm3 HCl.
Hydrate Lab The purpose of this lab is to analyze the percent water in a crystalline hydrate and to indentify the hydrate from a list of possible unknowns. The solid hydrate will be heated to remove the water, and the percent can be found by measuring the mass of the solid before and after heating. The hydrate will be indentified by comparing the percent water in the hydrate with the percent water calculated for the possible unknown. Before the lab there are pre-lab questions: 1. Describe the three general safety rules for working with a Bunsen burner.
What pieces of laboratory equipment would you use to measure the properties needed to determine the density of a substance? The piece of laboratory equipment needed to find mass is a balance and for volume a graduated cylinder. 3. Using the properties stated in question 1, write the formula for density. D=m/v 4.
NaOH (aq) + KHP (aq) —› Na+ (aq) + K + (aq) + P2- (aq) + H2O (l) NaOH (aq) + CH3COOH (aq) —› Na+ (aq) + CH3COO- (aq) + H2O (l) The titration of NaOH with KHP will identify the concentration of the NaOH provided. KHP will be weighed and its mass will be recorded. The moles of KHP will be calculated: Moles KHP = Mass KHP recorded / Molar mass of KHP = Mass of KHP recorded / 204.22g/mol The volume of NaOH will be determined by reading the
A fixed amount of water is added to a graduated cylinder and the volume of water is recorded. The object to be measured is then added to the graduated cylinder and the new volume is recorded. To determine the volume of the object the volume of water is subtracted from the volume of water with the object. Volume – Object = Volume object + water – Volume of water Materials: • Various percentages of zinc and copper mixtures o 0% Cu, 100% Zn o ~10% Cu, ~90% Zn o ~20% Cu, ~80% Zn o ~30% Cu, ~70% Zn o ~40% Cu, ~60% Zn o ~50% Cu, ~50% Zn o ~60% Cu, ~40% Zn o ~70% Cu, ~30% Zn o ~80% Cu, ~20% Zn o ~90% Cu, ~10% Zn o 100%Cu,0%Zn • Pennies o using 5, 10, 20 and 30 pre1982 pennies o using 5, 10, 20 and 30 post1982 pennies Procedure: 1.) From Penny Set A (Pre-1982), measure the mass of 1 penny and then of 2, 3, 5, 7, 9, and 13 pennies.
Are they all moving at the same speed? 2. How do the particles interact with the walls and lid of the container? These interactions contribute to the pressure on the walls of the container. Pressure is defined as force per unit area.
CHEMISTRY September 25, 2010 Experiment #5: Percentage of water in a Hydrate Summary of Principles In this lab, students will calculate the amount of water in an unknown hydrate. A hydrate is a compound with a specific number of water molecules associated with the ions of that compound. A hydrate may form when an anhydrous compound is exposed to atmospheric water or when the ionic compound is crystallized from an aqueous solution. An anhydrous compound is a substance without water. There are two parts to this lab.
To find out N2 you have to determine the mass of water produced in the reaction. This mass is the difference between the mass of initial compound (BaCl2•XH2O) and the mass of anhydrous salt (BaCl2). N2 is the ratio of the mass of the water produced in the reaction to the molar mass of