Chemistry Exam 1 Ch.2

Round the value 44.981 g to three significant figures.

45.0 g

You add 6.6 g iron to 26.10 mL of water and observe that the volume of iron and water together is 26.94 mL. Calculate the density of iron.

6.6/26.94-26.10=7.9 g/ml

How many moles of atoms are in 9.00 g of 13C?

9*1/13=.692

Without doing any calculations, determine which sample contains the most atoms.

a 1 g sample of carbon

Energy ______

is conserved in any process but can be transferred between the system and the surroundings

What is the meaning of the number of digits reported in a measured quantity?

the number of digits reflects the certainty in the measurement

Determine the number of significant figures in the measurement 6.07 m?

3

How many atoms are in 5.76 mol of pure silver?

3.47 × 10^24 atoms

(.692 mol 13C) Based on your answer in Part A, calculate the number of atoms in this amount of 13 C?

.692*(6.02*10^23)=4.17*10^23

How many moles of atoms are in a pure gold ring (24K) that has a mass of 6.62 g?

0.0336 mol

The conversion factor relating feet to meters is 1ft=0.305m. Keep in mind that when using conversion factors, you want to make sure that like units cancel leaving you with the units you need. You have been told that a certain house is 164 m^2 in area. How much is this in square fee?

1. .305m*.305m=.093025m^2 2.164/.093025=1762.9669 =1760

The density of iron is 7.87 g/mL. What is the mass of a 3.00 cm×4.00 cm ×1.00 cm block of iron?

1. 3.00cm*4.00cm*1.00cm= 12cm^3 2. 7.87*12 =94.4 g Remeber density=mass/volume mass=density*volume

What is the edge length of a cube that has a volume of 10.0 cm3?

1.00 × 10^3 cm

Backpackers often use canisters of white gas to fuel a cooking stove's burner. If one canister contains 1.45 L of white gas, and the density of the gas is 0.710 g/cm^3 , how many kilograms of fuel are contained in one canister?

1.03 kg

Determine the number of significant figures in the measurement 0.0030s?

2

Convert 9255 cm^3 to gallons.

2.445 gal

What is the difference between intensive and extensive properties?

An intensive property is independent of the amount of the substance, whereas extensive property depends on the amount of the substance

A block of metal has a width of 3.2 cm, a length of 17.1 cm, and height of 5.5 cm. Its mass is 1.4 kg. Calculate the density of the metal.

D = 1.4 kg / (3.2cm x 17.1cm x 5.5cm) =4.7g/cm^3

Intensive: Begins to melt at 1083.4 degrees Celsius reddish brown in color has a density o 8.96 g/ml

Extensive: has a volume of 5.68 mL has a mass of 50.89 g

Is the burning of natural gas in a stove exothermic or endothermic?

The burning of natural gas in a stove is exothermic.

What is the sign of the energy change?

The energy change is negative.

11.495 g of sodium contains 6.022× 10^23 atoms.

true