CHEM 141 - homework 1

The length of the side of a cube having a density of 12.6 g/ml and a mass of 7.65 g is ________ cm.

0.847

45 m/s = ________ km/hr

1.6 x 10^2

1 nanometer = ________ picometers

1000

14.3570 + 2.75 Express your answer in appropriate significant figures

17.11

How many significant figures does the number 0.51 have?

2

What is the mass of the silver sphere in kg? density = 10.49 g/cm^3 volume = 196 cm^3

2.06 kg

The temperature of -25 °C is ________ in kelvins.

248

he width, length, and height of a large, custom-made shipping crate are 1.22m, 3.22m, and 0.83m, respectively . The volume of the box using the correct number of significant figures is ________ m^3

3.3

Round the following number to four significant figures and express the result in standard exponential notation: 0.35462

3.546 × 10^-1

What is the kinetic energy of the silver sphere at the moment it hits the ground? (Assume that energy is conserved during the fall and that 100% of the sphere's initial potential energy is converted to kinetic energy by the time impact occurs.) density = 2.70 g/cm^3 volume = 196 cm^3

30 J

A temperature of 450. K is the same as ________ °F

351

The force of gravity acting on an object is F = mg, where m is the mass of an object and g is the acceleration of gravity (9.8 m/s^2). How much work do you do on the silver sphere if you raise it from the floor to a height of 1.9 m?

38 J

What is the velocity of the silver sphere at the moment it hits the ground? (Assume that energy is conserved during the fall and that 100% of the sphere's initial potential energy is converted to kinetic energy by the time impact occurs.) density = 2.70 g/cm^3 volume = 196 cm^3

5.4 m/s

The number 1.00430 has ________ significant figures

6

A wooden object has a mass of 10.782 g and occupies a volume of 13.72 mL. What is the density of the object determined to an appropriate number of significant figures

7.859 × 10^-1 g/mL

0.0584 / 0.671 Express your answer in appropriate significant figures

8.70 × 10^-2

952.9 - 140.7375 Express your answer in appropriate significant figures

812.2

(3.25 × 10^4)(0.2588) Express your answer in appropriate significant figures

8410

The force of gravity acting on an object is F = mg, where m is the mass of an object and g is the acceleration of gravity (9.8 m/s^2). How much work do you do on the aluminum sphere if you raise it from the floor to a height of 1.9 m?

9.8 J

cceleration due to gravity of a free-falling object is 9.8 m/s^2. Express this in millimeters/millisecond^2

9.8 x 10^-3

Convert this energy, 1.83 × 10^5 J to calories

E = 4.37 × 10^4 cal

Calculate the kinetic energy, in joules of a 1430-kg automobile moving at 16.0 m/s

KE = 1.83 × 10^5

Which change will lead to a larger change in the kinetic energy of an object, doubling its mass or doubling its speed?

doubling its speed

When the automobile brakes to a stop is the "lost" kinetic energy converted mostly to heat or to some form of potential energy? A. heat B. potential energy

heat

A combination of sand, salt, and water is an example of a ________. A. solid B. heterogenous mixture C. compound D. homogenous mixture E. pure substance

heterogenous mixture

Precision refers to ________. A. how close a measured number is to other measured numbers B. how close a measured number is to the true value C. how close a measured number is to the calculated value D. how close a measured number is to infinity E. how close a measured number is to zero

how close a measured number is to other measured numbers

Accuracy refers to ________. A. how close a measured number is to the calculated value B. how close a measured number is to zero C. how close a measured number is to other measured numbers D. how close a measured number is to the true value E. how close a measured number is to infinity

how close a measured number is to the true value

This is an example of potential energy being converted into what form of energy? A. kinetic energy B. elastic energy C. chemical energy D. thermal energy

kinetic energy

Does the potential energy of the two particles prior to release increase or decrease as the distance between them is increased?

potential energy decreases

Does the act of lifting the sphere off the ground increase the potential energy of the aluminum sphere by a larger amount, a smaller amount, or the same amount as the silver sphere?

smaller amount

Which one of the following is an intensive property? A. heat content B. temperature C. amount D. volume E. mass

temperature

In the following list, only ________ is not an example of a chemical reaction. A. the rusting of iron B. the condensation of water vapor C. dissolution of a penny in nitric acid D. the formation of polyethylene from ethylene E. a burning candle

the condensation of water vapor

If you release the spheres simultaneously, they will have the same velocity when they hit the ground. Will they have the same kinetic energy? If not, which sphere will have more kinetic energy?

the silver sphere will have more kinetic energy

Which of the following is an illustration of the law of constant composition? A. water and salt have different boiling points B. water can be separated into the other substances by a chemical process C. water is 11% hydrogen and 89% oxygen by mass D. water is a compound

water is 11% hydrogen and 89% oxygen by mass

"Absolute zero" refers to ________.

0 Kelvin

In which one of the following numbers are none of the zeros significant? A. 2002 B. 10.00 C. 0.00400 D. 0.0001 E. 21.00

0.0001

What is the mass of the aluminum sphere in kg? density = 2.70 g/cm^3 volume = 196 cm^3

0.529 kg