Take the density of gold, for example:. That is, the density value tells us that we have When we want to use density to convert from mass to volume, the numerator and denominator of density need to be switched.
For example, if we want to know the volume of A cork stopper from a bottle of wine has a mass of 3. If the density of cork is 0. Care must be used with density as a conversion factor. Make sure the mass units are the same, or the volume units are the same, before using density to convert to a different unit. Often, the unit of the given quantity must be first converted to the appropriate unit before applying density as a conversion factor see Example 7.
Acetone has a density of 0. We start with what is given, What is the mass in grams of 0. Density of olive oil can be found in Table 1. There are other units in chemistry that are important, and we will cover others in the course of the entire book. One of the fundamental quantities in science is temperature. Temperature is a measure of the average amount of energy of motion, or kinetic energy , a system contains. Temperatures are expressed using scales that use units called degrees , and there are several temperature scales in use.
Science also uses other scales to express temperature. By comparing the Fahrenheit and Celsius scales, a conversion between the two scales can be determined:. Using these formulas, we can convert from one temperature scale to another. The number 32 in the formulas is exact and does not count in significant figure determination.
T he average internal temperature of a human is The warmest month for Rochester, New York is July with an average high temperature of The fundamental unit of temperature another fundamental unit of science, bringing us to four in SI is the Kelvin K.
The Kelvin temperature scale note that the name of the scale capitalizes the word Kelvin , but the unit itself is lowercase uses degrees that are the same size as the Celsius degree, but the numerical scale is shifted up by That is, the conversion between the Kelvin and Celsius scales is as follows:.
For most purposes, it is acceptable to use instead of The reason that the Kelvin scale is defined this way is because there exists a minimum possible temperature called absolute zero.
The Kelvin temperature scale is set so that 0 K is absolute zero, and temperature is counted upward from there. Normal room temperature is about K, as seen in the following example.
What is this temperature in Kelvin? Figure 1. Note that science uses the Celsius and Kelvin scales almost exclusively; virtually no practicing chemist expresses laboratory-measured temperatures with the Fahrenheit scale. In fact, the United States is one of the few countries in the world that still uses the Fahrenheit scale on a daily basis. The other two countries are Liberia and Myanmar [formerly Burma]. Fahrenheit, Celsius, and Kelvin Temperatures. Because degrees Fahrenheit is the common temperature scale in the United States, kitchen appliances, such as ovens, are calibrated in that scale.
People who live at high altitudes, typically 2, ft above sea level or higher, are sometimes urged to use slightly different cooking instructions on some products, such as cakes and bread, because water boils at a lower temperature the higher in altitude you go, meaning that foods cook slower.
Good cooks need to be aware of this. At the other end is pressure cooking. A pressure cooker is a closed vessel that allows steam to build up additional pressure, which increases the temperature at which water boils.
Great care must be used with pressure cookers because of the high pressure and high temperature. When a pressure cooker is used to sterilize medical instruments, it is called an autoclave. Other countries use the Celsius scale for everyday purposes. Advanced Search. Sign In. Skip Nav Destination Article Navigation. Close mobile search navigation Article navigation. Volume 5, Issue Previous Article Next Article.
Article Navigation. October 01 Arps J. This Site. Google Scholar. J Pet Technol 5 10 : 17— Instead, relative density was determined by observing whether a bag of one liquid floated or sank in another liquid. A bag of liquid that sank was determined to be more dense than the liquid in the beaker. A bag of liquid that floated was determined to be less dense than the liquid in the beaker. The motion of any object is due to forces , which are pushes or pulls.
Vertical—up-and-down—movement of water masses in the ocean can be explained in terms of two forces. The gravitational force G of the earth pulls downward and is proportional to the mass of an object. The gravitational force on an object is also called weight. The force due to gravity is greater on objects that are more massive, or weigh more.
The buoyant force B of water pushes up. In the third century B. He observed that the volume of water pushed out of a tub, or displaced, by an object was equal to the volume of the object. The buoyant force of the water is equal to the weight of the water displaced.
An object accelerates when the forces on that object are unequal. Although acceleration is commonly used to describe an object that is speeding up, the scientific definition of acceleration means changing speed. An accelerating object can be speeding up or slowing down.
An object will always move in the direction of the greater force. An object may accelerate downwards sink or upwards rise in a body of water.
If all of the forces on an object are balanced, there is no acceleration. In this case, the object may not move—like a book sitting on a flat table—or the object may move at a constant speed—like a car traveling at a steady 80 kilometers per hour.
In the water, an object might remain still either at the surface or within the water column. Three cubes of the same size, but with different masses and thus different densities, are placed in three beakers of water Fig. Because the cubes are identical in volume, they displace the same amount of water. Buoyant force is represented in Fig.
These arrows are the same length for each of the cubes, indicating that the strength of the buoyant force acting on each cube is the same. Because the masses of the cubes are not equal, the gravitational force G acting on each cube is different. Gravitational force is represented in Fig. These arrows are different lengths for each cube, indicating that the amount of the gravitational force is different for each cube.
The downward pointing arrow in Fig. The downward pointing arrow is the longest in Fig 2. The density of the cube relative to the density of water determines if the cube will float, sink, or be neutrally buoyant:.
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