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# chem 11 Lesson 1

### Chemistry 11 Lesson 1 Intro to Chemistry

Question | Answer |
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What are the Scientific Notation Rules? | If a numerical value is less than 1, a ‘0’ precedes the decimal point. Example: 0.134 NOT .134. Long numbers are separated by space in groups of 3 from either side of decimal point (no commas and not required with four-digit numbers). Ex:1 234.769 54 |

What are the Scientific Notation Steps? | Step 1: To change a reg no. to scientific notation, move decimal place so 1 non-0mdigit appears to its left. 2: Drop all non-signif zeros. 3: x this no. by 10n ‘n’ = no of places decimal place has moved (n is + for moves to left and - for moves to right). |

SI base units | The International System of Units – the metric system.Symbol Unit Quantity s second time kg kilogram mass m metre length J joule energy, work W watts power L litre volume Pa Pascal pressure oC degree Celcius temperature mol mole amount o |

What is Chemistry? | the science that deals with the properties and reactions of materials. It is concerned with the identification, characterization, and transformations of matter, and with the energy changes accompanying these transformations. |

What's the difference between Observations & Conclusions? | Observations are made with the body's senses and are sometimes aided by the use of measuring instruments such as a balance or a thermometer. A conclusion is an inference or an interpretation of an observation. |

What are Qualitative observations? | descriptions or data collected by the body's sense: The vinegar tastes sour. The flame is bright white. The metal is easily scratched. |

What are Quantitative observations? | involve the recording of numerical data and requires the aid of a measuring device of some kind. The starting mass of the salt was 2.56 grams. The candle burned for 5 minutes. The temperature ended up at 29.4oC. |

Scientific Notation | a short-hand of writing numbers |

examples of derived entities | Volume (m3), speed (m/s) and moment of inertia (kg.m2) |

What is Dimensional analysis? | method for solv probs. Dimen analy units+ cancel of units in equations. To use units,determine u ans sh have. Org data to yield units. may be algebraic variables in cals + mult/div same way as no. Un in equat r cancel til rem units = expect units=ans prob |

Density | amount of matter present in a given volume of a substance (mass per unit volume –usually in g/mL or g/cm3). |

Precision and accuracy | Precision measures the agreement between results of repeated measurements and is usually controlled by the size of the scale of the measuring device. Accuracy, measures the agreement between a measurement and the accepted standard value. |

Significant Digits | Measurement of quantities vary continuously (length, mass, volume, temperature, etc.) subject to uncertainty. For mass recorded as 54.87 g understood "7" is an estimate. Significant digits are uncertain digits +1 uncertain/estimated dig in recorded mea |

precision | the degree of exactness to which the measurement of a quantity can be reproduced. |

Adding & Subtracting | answer must have the same number of decimal places as the least certain number used in the problem -- the "weak link" in the chain of figures. The process may require some rounding off. Rounding off may be necessary for non-fraction values too. |