Mod 3

52問 • 1年前

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is a qualitative term used in determining the DEGREE OF CONFORMITY of a test result to a true or accepted value.

Accuracy

In addition, TRUE VALUE is usually derived from the use of a — or standard reference material () in which quantities or amounts are certified and are accompanied with a certificate of analysis.

certified reference material (CRM)

, is the quotient of the summation of all data and the number of data involved.

Mean (X), also known as average

The closer is the mean to the accepted value, which is 2 mg Na, the higher is the — of the data.

accuracy

Another way to determine the DEGREE OF ACCURACY in a measurement is through the magnitude of —.

error

refers to the absolute value of the difference between the theoretical value (Le, the accepted value) and experimental value (ie, usually the average value).

Error

Absolute Error

|theoretical value–experimental value|

Relative Error

AE/TV × 100

pertains to the consistency of achieving the SAME RESULTS REPEATEDLY even if the value is far from the true value.

precision

To say that a set of data is precise means that the data are close in value to one another. One statistical tool to measure precision of a set of data is —.

standard deviation

— describes how spread out or the data are, and it is always equal to or less than one. The lower the SD value, the higher is the precision of data.

Standard deviation (SD)

To compute SD, use equation 1.13.

SD = √summation of (x-xbar)²/n-1

is the sumplified expression for a very large or very small sunsber or quantity.

Scientific notation

is a temperature dependent physical quantity that is specific to pus substances and is specifically defined as the mass (m) per unit volume (0)

Density (d)

Units of densities are expressed in — for solids, and — for liquids. Mathematically, density is expressed as

g/cm g/ml, or g/L d=m/v

This property is valuable in distinguishing one substance to another.

density

measures the compactness of an object or the quantity per unit volume. Objects at different phases show different levels of compactness.

Density

As the temperature increases, the amount of — of the particles also increases and the volume they occupy or their — also increases. However, the level of compactness of substances decreases. Thus, the — has the highest density among the three. At standard temperature, the density of a gas is less than a liquid, and, in turn, the density of a liquid is less than a solid (i.e., except in water).

kinetic energy compactness solid

Three Phases of Malter is made of particles that give its mass and volume.

Matter

The arrangement and attraction between these particles result in —. Matter can exist as solid, liquid, or gas. How can you differentiate one from the other

different phases of matter

In the — phase, the molecules are tightly bound to one another by molecular forces of attraction.

solid

A — has its own shape and fixed volume.

solid

In the — phase, the molecules are weakly attracted to one another as compared to the solid phase.

liquid

Like solids, — have fixed volumes, but they take the shape of their containers.

liquids

Last, the attraction among molecules is the weakest in the — phase. Thus, it does not have a fixed volume or shape

gas

A change in — can physically transform a substance. This occurs in a —, a physical change where the substance undergoes changes without changing its chemical composition

temperature or pressure phase transition

The two types of properties associated with matter are —

physical properties and chemical properties.

are properties that can be measured and observed without changing the material's chemical composition.

Physical properties

This includes the properties that you easily identify just by mere observation such as the appearance, color, texture, and odor of the material.

Physical properties

Other physical properties of matter are —4 of the material.

melting point, boiling point, solubility, and density

—, on the other hand, describe a material's possibility to undergo chemical change in its chemical composition.

Chemical properties

Examples of chemical properties include

flammability, toxicity, reactivity to water and oxygen like rusting, heat of combustion, PH, enthalpy of formation, oxidation states, chemical stability, salt formation, and types of chemical bonds and material forms

Physical properties of matter can further be classified as —.

intensive or extensive

are substance-specific properties that do not depend on the amount of the substance.

Intensive properties

One illustration of this property is the density of water. If you put different amounts of water in three different sizes of cups, the density of water will still be the same.

Intensive properties

Other intensive properties include

color, luster, malleability, conductivity, hardness, melting point, freezing point, and boiling point of the material.

are properties that do depend on the amount of substance of the material.

extensive properties

Whenever the amount of the substance changes, the substance's — also change.

extensive properties

One illustration of this property is the mass of table salt. As you put more salt into a container, the mass of the salt also changes. That is an example of an —.

extensive property

Aside from mass, other extensive physical properties are —3

weight, volume, and length.

Matter changes. These changes can be physical changes or chemical changes. For example, melting of ice is a change of phase from solid to liquid; this is a —. On the other hand, rust, which is chemically known as ferric oxide (Fe₂O,), is formed when the house's iron sheet roofing is exposed to rainwater and air for a long period of time. The chemical composition of rust is different from that of the iron sheet: thus, this is a —

physical change chemical change.

Matter, whether it is solid, liquid, or gas, is classified as a —.

pure substance or a mixture

If the components of matter can separated by physical means, then that is a —.

mixture

Anything that cannot be broken down through physical means is a —.

pure substance

A pure substance can be classified as an —.

element or a compound

If a pure substance can be broken down into simpler forms using chemical means, you are dealing with a —. If it cannot be simplified, then it is an —

compound element.

The law that governs the combination of atoms to form compounds is the law of —2. It states that when two or more elements combine to form a compound, they follow a definite composition and proportion.

constant composition or definite proportion

A — is made up of elements that are CHEMICALLY BONDED in fixed ratios whereas components of a mixture are not chemically bonded

compound

are forms of matter with no definite properties and are not combined chemically.

Mixtures

This means that the materials in a — retain their characteristics, or they have no uniform composition.

mixture

A — mixture is a mixture in which only one phase is visibly seen, whereas a — mixture has at least two different phases of matter or visible components.

homogeneous heterogeneous

An example of a homogeneous mixture is — solution.

dextrose or glucose

ALERTNESS

Trix Soriano · 24問 · 2年前

ALERTNESS