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Understanding Chemical Reactions: Types, Rates, and Factors

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Chemical Reactions

occurring at low temperatures are
                _______low______ than reaction rates of chemical reactions occurring at high
temperatures.

40. Increasing pressure causes gas particles to             ______collide_______________. This
                ________increases______________ the reaction rate of a chemical reaction.

41. All reactions require    ___activation energy___________ for chemical bonds to begin breaking.

iPhone Pricing Strategy: A Financial Analysis of Apple's Potential Price Increase

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Exercise 3 – Analyzing the Financial Impact of Price and Volume Changes on Apple iPhones

Apple iPhone Sales and Manufacturing Costs

In 2014, Apple sold approximately 150,000,000 iPhones at a price of $640 per unit. The company's average manufacturing cost per iPhone is detailed in Table 1.

Table 1 – iPhone Unit Manufacturing Cost Estimates
ComponentCost (USD)
Flash Memory & RAM20.85
Display & Touchscreen44.00
Processor17.50
Sensors6.50
Cameras18.00
Cellular Radio34.00
Wireless Radio5.00
Battery4.50
Power Management8.50
Mechanical Parts33.00
Packaging7.00
Production8.00
Licensing Fees20.00
Source: http://www.digitaltrends.com/mobile/iphone-cost-what-apple-is-paying/

Table 2 outlines Apple's fixed costs associated with its iPhone business.

Table 2 –
... Continue reading "iPhone Pricing Strategy: A Financial Analysis of Apple's Potential Price Increase" »

Extraction of Metals and Chemical Reactions

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  1. Gold Extraction

    Gold is found mainly as the metal itself in the earth because it has a low reaction rate, which prevents easy oxidation.

Carbon Extraction of Zinc

Carbon can be used to extract zinc because carbon has a higher reaction rate than zinc.

Sodium Extraction

Sodium was not extracted until 1807 because sodium attaches itself very strongly to other elements, making it difficult to separate and obtain a pure substance.

Limestone

i) Name of Material: Limestone

Reason why this metal is used: It decomposes silicon dioxide in the heat of the furnace to calcium oxide.

ii) Word Chemical Equation for the Reaction of Iron Extracted from Iron Ore when a Gaseous Oxide of Carbon Reacts with Iron Oxide: FeO + CO = Fe + CO2

Aluminium Extraction

i) Why a Mixture... Continue reading "Extraction of Metals and Chemical Reactions" »

Matter, Solutions, and Gases: Chemistry Fundamentals

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Matter Composition

- Matter: Formed of two or more pure substances.

Heterogeneous Mixtures

1. Heterogeneous: Non-uniform composition.

Homogeneous Mixtures

2. Homogeneous: Uniform composition, small particles.

Solutions

- Solution: Homogeneous mixture, small particles, liquid solutions are transparent.
- Solute: Smaller amount.
- Solvent: Larger amount, often water (aqueous).

Colloids

- Colloid: Mixtures with larger particles.

Electrolytes

- Electrolytes: Allow water to conduct electricity due to ions in the solution. Strong electronegativity.
Examples:
- Acids: HCl, HNO3, H2SO4
- Salts: K+, Na+, NH4+, NO3-
Example of Dissociation:
NaCl → Na+ + Cl-

Non-Electrolytes

- Molecules, polar for H2O, sugars; polar solute dissolves in a polar solvent.

Hydrogen Bonding

-... Continue reading "Matter, Solutions, and Gases: Chemistry Fundamentals" »

Chemical Analysis of Salts: Anions and Cations

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Preliminary Test

Color of the Salt

Colourless

Absence of Cu 2+, Fe 2+, etc

Odour of the Salt

Ammoniacal smell

Vinegar smell

NH4

Acetate ion

Solubility

In water with no precipitate with Na2CO3

In dil HCl, soluble

NH4

No Group 1 cations

Salt is heated in a dry test tube

Colorless gas turns milky

Reddish brown fumes

Smell of ammonia

Pleasant smell

Carbonate

Nitrate ion

NH4

Acetate ion

Flame Test

Pale green

Brick red

Ba

Ca

Ash Test

Blue ash

Al


Systematic Analysis for Anions

Dil HCl is added to a little of the saltBrisk effervescence of a colorless gasCO3
Salt is rubbed with dil H2SO4 in a watch glassVinegar smellAcetate
Salt is heated with conc H2SO4Colorless pungent smelling gas is evolved and dense white fumes are produced when a glass rod dipped in NH4OH is shown near the mouth
... Continue reading "Chemical Analysis of Salts: Anions and Cations" »

Chemical and Biological Processes: Reactions, Compounds, and Cell Division

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Chemistry

What is a Chemical Change?

A chemical change is a reaction that causes new substances with new properties to form.

Evidence of a Chemical Change:

  • Gas bubbles
  • Light/Heat
  • Colour change (must be combined with another chemical evidence)
  • Precipitate forms

Physical Properties

Examples of physical properties include:

  • Melting point
  • Boiling point
  • Atomic mass
  • Colour
  • Malleability
  • Conductivity
  • Lustre

Key Terms:

  • a) Valence electron: electron in the outermost shell/orbit
  • b) Stable octet: full valence shell (usually 8)
  • c) Cation: positively charged ion (loses electron)
  • d) Anion: negatively charged ion (gains electron)

Chemical Formulas:

  • Aluminum chloride: AlCl3
  • Lead (IV) oxide: PbO2
  • Copper (II) nitrate: Cu(NO3)2
  • Beryllium carbonate: BeCO3
  • Sodium phosphide: Na3P
  • Barium hydroxide:
... Continue reading "Chemical and Biological Processes: Reactions, Compounds, and Cell Division" »

Fractional Distillation and Cracking Polymers: Separating Crude Oil

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To separate crude oil into its fractions, we use fractional distillation. This process occurs in an oil refinery. The crude oil is heated to about 350 degrees Celsius in a column that gets cooler higher up. Each fraction will evaporate and rise up the column until it reaches a part that is cool enough to condense it. The liquid goes into its respective tube and is separated from the rest of the crude oil. The smallest alkanes, which have a lower boiling point, will rise to the top. The largest fraction, bitumen, never evaporates and falls as a liquid to the bottom.

Cracking

Crude oil contains a mix of alkanes. Shorter alkanes are the most useful as fuels. We can obtain more shorter alkanes by breaking down the larger ones. This process is called... Continue reading "Fractional Distillation and Cracking Polymers: Separating Crude Oil" »

Understanding Dental Materials: Properties and Clinical Significance

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Chemical Bonding in Dental Materials

Primary Bonds

Factors Influencing Material Properties:

  1. Type of bond between atoms and molecules
  2. Inter-atomic distance
  3. Atomic packing

Matter: Any substance that has mass and occupies space.

Atom: The fundamental unit of matter, consisting of a central nucleus (protons and neutrons) surrounded by electrons.

Types of Primary Bonds:
  • Ionic Bond: Attraction between positive and negative ions. Characteristics: Strong, heat resistant, insulator, insoluble in organic solvents, basic bond in ceramics.
  • Covalent Bond: Sharing of electrons between two atoms. Characteristics: Strong, insulator, water insoluble, basic bond in polymers.
  • Metallic Bond: Attraction between positive atomic cores and free electrons. Characteristics: High
... Continue reading "Understanding Dental Materials: Properties and Clinical Significance" »

Essential Chemistry Formulas and Concepts

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Temperature Conversions

  • Celsius to Fahrenheit: F = (9/5) * C + 32
  • Celsius to Kelvin: K = C + 273

Atomic Structure

  • Atomic Mass: Protons + Neutrons (upper left symbol)
  • Atomic Number: Protons (bottom left symbol)

Quantum Mechanics

  • Planck's Constant (h): 6.6260755 x 10-34 J*s
  • Energy of a Photon: E = hv or E = hc / wavelength

Electronic Transitions

  • Absorption: When energy is absorbed by an atom, an electron is excited to a higher energy level or orbital.
  • Emission: When an electron relaxes from a higher energy orbital to a lower one, it emits a photon.

Filling Orbitals

s = 2, p = 6, d = 10, f = 14

1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 5f

Periodic Trends

  • Atomic Radius: Increases down a group and decreases across a row.
  • Ionization Energy: Amount of energy
... Continue reading "Essential Chemistry Formulas and Concepts" »

Coh3 chemical name

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in the RUTHERFORDS atomic model, the electrons are orbiting around the nucleous. In the nucleus are the neutrons and protons. BOHRS atomic model, the electrons move in stable orbits around the nucleus. Each orbit present a different number of electrons. How do we identify isotopes? By the name of the chemical element followed by its mass number. The elements in the periodic table are grouped: increasing atomic number(periods), similarity in physical and chemical elements(columns). Crystals are a gorup of atoms ordered ina geometric structure.