CHM151 Chapter 1 - Basic Concept of Chemistry

What is a law

A law • is a concise verbal or mathematical statement of a relationship between phenomenon that is always the same under the same conditions. • (The law summarize the data that remains consistent. Every time (the law say when you summarize the data this one thing happens every time) For example, newton second law of motion say that force equals mass times the acceleration. What this law means is that an increase in the mass or the Acceleration of an object will always increase its force, proportionally, and a decrease in mass or acceleration will always decrease the force (Every time force goes up mass goes up and it is consistent. Every time u try . Therefore, it is a law)

meter

A meter is equal to 100 centimeters 1 meter = 1000 millimeters A kilometer is equal to 1000 meters. 1 Gallon = 4 quarts = 8 pints = 16 cups= 128 fluid ounces

Chemist distinguish among several subcategories of matter based on composition and properties The classification of matter includes substances, mixtures, elements, and compounds as well as Atoms and molecules The two main categories of matter are substances and mixtures

A substance 1) is a form of matter that has a constant or individual composition and distinct property (one element) 1). Example water, sugar, oxygen, ammonia,gold A mixture 1) is a combination of two or more substances in which the substance retain there distinct identities ex a human being is made up of blood, water and oxygen ex air, soft drinks, milk, cement, The way to separate a matter is to physically separate the matter ex boil, condensation

density volume

density=mass/volume volume= mass/density mass= density x the product

naming compounds ionic compounds

ionic compounds- compounds formed by a metal and nonmetal. usually binary first one is a metal ans 2nd is nonmetal ex NaCl= sodium chloride the anion is named by taking the 1st part of the element and ading

The data obtained in a research study may be both qualiatative and quantitative

qualitative • 1) consist of general observation about the system Quantitative • 1) comprising numbers obtained by various measurements of the system When it's all done then you cycle back around and do it again when you cycle back around, you'll get a hypothesis Prof. example A scientific method is a process of getting to certain answer based on the question asked When the experiment have been completed and the data have been recorded the next step in the scientific method is interpretation, meaning that the scientists attempts to explain the observed phenomenon. Based on the data that were gathered, the researcher formulates a hypothesis

what is chemistry

1.1 intro to chemistry Chemistry • is the study of matter and the changes it undergoes • Chemistry is often called the central science because a basic knowledge of chemistry is essential for students of biology, physics, geology, ecology, and many other subjects. 1.2. The study of chemistry (read that)

define scientific method

1.3. The scientific method All science including the social science, employee variations of what is called the scientific method The scientific method 1) a systematic approach for research For example • A psychologist who wants to know how noise effects people's ability to learn chemistry and a chemist interested in measuring the heat given off when hydrogen gas burns the ear would follow roughly the same procedure in carrying out their investigation.

Physical property of matter

1.6 physical and chemical properties of matter substances are identified by their properties as well as by their composition. Ex color, melting point, boiling point. Our physical properties. Physical property • can be measured and observed without changing their composition or identity of a substance. • For example, we can measured the melting point of ice by heating a block of ice and recording the temperature at which the ice is converted to water, water, the first from ice only in appearance, not in composition, so this is a physical change, we can freeze the water to recover the original ice. Therefore, the melting point of a substance is a physical property. Similarly, when we say the helium gas is lighter than air, we are referring to a physical property • physical property can be measured and observed it does not change its composition

conversion

1cm=1x10^-2m or 0.01meters 1L=1000 cm^3 1ml= 10^-3grams or 0.001grams 0.808g=1cm^3 1kg=1000g 1cm^3=1x10^-6= 1meter=0.1 decimeter

conversion factor

1lb=453.6 g 1L=1000 ml 1ml=0.001L 1inc=2.54cm 1g=1000mg 1mg=0.001g

Chemical properties-undergo changes in its composition

Chemical properties-undergo changes in its composition • on the other hand, the statement hydrogen gas burns in oxygen gas to form water describes a chemical property of hydrogen because to observe this property. We must carry out a chemical change in this case burning. After the change. The original chemical substance. The hydrogen gas, will have vanished, and all that will be left is a different chemical substance which is water. We cannot recover the hydrogen from the water by means of physical change, such as boiling or freezing, so this is the difference between chemical property and physical property. For example, every time we hardball and egg we bring about a chemical change. When subject to a temperature of about 100°C. The yoke and the egg white undergo changes that alter not only their physical appearance, but their chemical makeup as well. When eaten . The egg is changed again by substances in our bodies called enzymes. This digestive action is another example of a chemical change. What happens during digestion depends on the chemical properties of both the enzymes and the food • another example is when you fried egg you denatured the property • with physical properties, you can do the opposite effect and go back to the original property, but chemical property. You cannot. The bonds are forever broke

what is a Hypothesis?

Hypothesis 1) a tentative explanation for a set of observations Further experiments are devised to test the validity of the hypothesis in as many ways as possible and then the process begins a new. After large amount of data has been collected, it is often desirable to summarize the information in a concise way as a law. (In other words , after you get your hypothesis and you continue to test the hypothesis to rule your process until you could put them into a category in a form of laws or theories) (Example of scientific method I would like to be a doctor, perform the experiment I take chemistry i do well or poor., Perform the experiment, I take chemistry class, which is the experiment and then I make my observation i did bad so from the observation I should try music.) Did you make your hypothesis, said she did well in music you should become a musician instead of a doctor then you go back to the cycle and perform the experiment u join a band etc then u make the observation and interpret the data)

what is a theory

Hypothesis that survived many experimental test of their validity may evolve into theories. A theory 1) is a unifying principle that explains a body of facts and/or those laws that are based on them (It explains a body of facts but it fails sometimes . Therefore, it evolves over time) (. Think of the data is being a cup and you fill the cup with data and then you keep adding information to it and you're waiting for things to look similar, so you do a series of tests and you notice that after 20 tests. There are some consistency of the outcome and then after 20 tries the consistency is broken, so therefore there is no theory to it) So a law happens all the time. As long as you have the same conditions, you will produce the same data A theory happens all the time, but there is a point where it breaks down and does not happen all the time

Substances can be either elements or compounds define both of them

If you break down pure substance . You will get elements and compounds If you pack a bunch of pure substances together, you will get a mixture and if you break down a bunch of pure substances, you will get elements Substances can be either elements or compounds An element • is a substance that cannot be separated into simpler substances by chemical means (118 elements have been positively identified) (ex carbon, nitrogen, oxygen) compounds • are substances composed of atoms of two or more elements chemically united in fixed proportions • for instance, water, water is made up of two parts of hydrogen and one part oxygen unlike mixtures compounds can be separated only by chemical means into their pure components (sugar ammonia, h20) in order to break water and get it to go back to oxygen and hydrogen you have to break the bond between oxygen and hydrogen)

1.4 classifications of matter We define chemistry as the study of matter and the changes it undergoes What is Matter?

Matter 1) is anything that occupies space and has mass matter includes things we can see and touch. For example, water, earth, and trees as well as things we cannot, such as air. Thus, everything in the universe has a chemical connection

Mixtures are either homogeneous or heterogeneous define both of them.

Mixtures are either homogeneous or heterogeneous When a spoonful of sugar dissolves in water, we obtain a homogeneous mixture Homogeneous Mixture 1) in which the composition of the mixture is Visually the same throughout (only have one thing) If sand is mixed with iron fillings, however the sand grains and Iron and fillings remain separated. This type of mixture is called a heterogeneous mixture Heterogeneous mixture 1) the composition is not uniformed (has many things like humans blood,fat, water) Ex oil and water, sand and rocks, food coloring Homogeneous mixtures: They are mixtures in which the constituents don't appear separately 1. Blood 2. Sugar solution when sugar is completely dissolved. 3. Mixture of alcohol & water 4. A glass of orange juice 5.salty water (where the salt is completely dissolved) 6.brewed tea or coffee 7.soapy water 8.a dilute solution of hydrochloric acid 9.hard alcohol 10.wine Heterogenous mixtures: constituents appear seperatly 1. Oil & water. 2. Soil sample 3.sandy water 4.carbonated beverage or beer (the CO2 gas is mixed with the liquid) 5.orange juice with pulp in it water with ice cubes in it 6.chicken noodle soup 7. sand in a desert

si units and prefix see pg 13

Si units • see page 12, and page 13 in table 1.2 table 1.3 • for many years, scientists recorded measurements in metric units, which are related to similarly, that is my power of 10 in 1960. However, the Gen. conference of weight and measures the international authority on units propose a revised metric system called the international system of units. Table 1.2 shows the seven SI base units. All other units of measurement can be derived from these base units like metric units SI units are modified in decimal fashion by a series of prefixes as shown on table 1.3 • measurements that we will utilize frequently in our studies of chemistry include time mass volume density and temperature (you can get the resolution of the instrument based on what it gives you when you take the measurement and you see the numbers on the analytical balance, you know, is that it gives you four digits were as the triple beam balance give you two digits after the decimal. Then you look at the uncertainty of the measurements between the two scales, which will be the last digit. And we can see the analytical has higher resolution instrument because it gives you more sure figures compared to the balance scale. The uncertainty in the balance scale appears more sooner due to the amount of significant figures.) See prefixes on table 1.3 prefixes give you information about what number you are looking at and how many zeros you have in scientific notation

what are the steps in carrying out the scientific method?

Steps in carrying out the scientific method • The first step is to carefully define the problem • The next step includes performing experiments • The third step is to make careful observation, And recording information or data • and the last step is to explain

density

The density of a substance is equal to the ratio of mass of substance to the volume. The formula for density is; Density = mass / volume Density = 3.12 g/ cm3 mass = 28.1 grams Volume = mass / density Volume = 28.1 grams / 3.12 grams / cm3 Volume = 9 centimeter cube

The three states of matter

The three states of matter All substances at least in principle can exist in three states • solid liquid and gases as shown in figure 1.6 gases differ from liquid and solid in the distance between the molecule. In a solid molecules are held close together in an orderly fashion with little freedom of motion. Molecules in a liquid are close together but are not held so rigidly in position and can move past one another. In a gas. The molecules are separated by distance that are large compared with the size of the molecules. The three states of matter can be inter-converted without changing the composition of the substance. Upon heating a solid, for example, ice will melt to form a liquid water. The temperature at which this transition occurs is called the melting point. Further heating will convert the liquid into a gas. This conversion takes place at the boiling point of the liquid. On the other hand, cooling and gas will cause it to condense into a liquid. When the liquid is cooled further, it will freeze into the solid form. When You go from solid to liquid to gas, you are not breaking any bonds you are just separating them for separating the molecules. When you're talking about solid, liquid and gas you're talking about how the molecules are arranged. When you place one molecule close together to another without moving That is when you get a solid. When you introduce temperature . The molecules will move a little further and you will get a liquid. When you introduce more heat than the molecules will try to get as far as way together and you'll get a gas. In order to go from gas to liquid to solid. You do the opposite and you cool the system, just by changing the temperature.

convert degrees Fahrenheit to degrees Celsius. convert degrees Celsius to degrees Fahrenheit convert degrees Celsius to Kelvin

To convert degrees Fahrenheit to degrees Celsius. We write the following C=( F-32F)x5/9 the following equation is used to convert degrees Celsius to degrees Fahrenheit F=9f/5c x (c)+32F both the Celsius and the Kelvin scale have units of equal magnitude, that is one degrees Celsius is equivalent to one Kelvin experimental studies have shown that absolute zero on the Kelvin scale is equivalent to -273.15 Celsius on the Celsius scale. Thus, we can use the following equation to convert degrees Celsius to Kelvin K=(C+ 273.15C)1k/1c we will frequently find it necessary to convert between degrees Celsius and degrees Fahrenheit and between degrees Celsius and kelvin. Example 1.3 illustrates these conversions

MOLECULAR COMPOINDS

USUALLY compose of nometal elements

volume see pg 14 1L= 1ML=

Volume • the SI unit of length is the meter and the SI derived units for volume is the cubic meter. Generally, 1L= 1000ml =1000cm 1dm^3 1cm^3 1 cm^3 = (1 x 10^-2 m)^3 = 1 x 10^-6^ m^3 1 dm^3 = (1 x 10^-1 m)^3 = 1 x 10^-3 m^3 1 L = 1000 mL = 1000 cm^3 = 1 dm^3 1 mL = 1 cm^3

all measurable properties of matter fall into one of two additional categories extensive property and intensive properties define both of them

all measurable properties of matter fall into one of two additional categories extensive property and intensive properties the measured value of an extensive property • depends on how much matter is being considered • mass-which is the quantity of matter in a given sample of a substance is an extensive property more matter means more mass. • Values of the same extensive property can be added together (for example, to copper pennies will have a combined mass that is the sum of the masses of each penny, and the length of two tennis courts, is the sum of the lengths of each tennis court • volume defined as length, cubed is another extensive property. The value of an extensive quantity depends on the amount of matter. Extensive- • quantity specific (relies on how much of the substance you have) • mass will defer • volume will defer • length will defer Intensive • quantity independent (doesn't matter how much matter you have the property will remain the same) • density defined as the mass of an object divided by its volume is an intensive property • density will stay the same • so is temperature • ex . Suppose that we have two beakers of water at the same temperature. If we combine them to make a single quantity of water in a large beaker, the temperature of the large quantity of water will be the same as it was in two separate beakers. Unlike mass, length, and volume, temperature and other intensive properties are not additive • density= mass/volume ....

Mass and weight

the term mass and weight are often use interchangeable, although strictly speaking, they are different quantities. Were as mass is- a measure of the amount of matter in the object Weight-technically speaking is the force that gravity exerts on an object. mass - measure of the quantity of matter SI unit of mass is the kilogram (kg) 1 kg = 1000 g = 1 x 10^3 g weight - force that gravity exerts on an object In Apple that falls from a tree is pulled downward by efforts gravity. The mass of the Apple is constant and does not depend on its location, but it's weight does see example on page 13 the SI units of mass is the kilogram. Unlike the units of length and time, which are based on natural processes that can be repeated by scientists anywhere the kilograms defined in terms of a particular object in chemistry. However, the small a gram is more convenient 1 kg= 1000 g=1x10^3g (the si unit of mass is the kilogram the mass versus the weight is independent where the mass is Some object that you will weigh) weight is mass times gravity times height. Weight is a quantity that is place specific because it depends on gravity. See page 13

Temperature scale

three temperature scale are currently in use. There units are Fahrenheit, degrees Celsius, and Calvin. The Fahrenheit scale, which is the most commonly used scale in the United States outside the laboratory defines the normal freezing and boiling point of water to be exactly 32°F and 212 Fahrenheit, respectively. The Celsius scales divide the range between the freezing point (0°C) and boiling point (100°C) of water into 100°. As table 1.2 shows the Calvin is the si base unit of temperature. It is the absolute temperature scale. By absolute we mean that the zero on the Kelvin scale denotes by zero k is the lowest temperature that can be attained theoretically. On the other hand, 0°F and 0°C are based on the behavior of an arbitrarily chosen substance. Water. Figure 1.11 compares the three temperature scales. The size of a degree on the Fahrenheit scale is only 100/180 or 5/9 of a degrees on the Celsius scale.