What is Chemistry? מהי כימיה? Chemistry is the study of matter and its composition, structure, properties, and reactions Chemsitry occurs all around you, for example, when you cook food, add chlorine to your pool, digest food, and drop an antacid tablet in a glass of water.

Classification of Matter סיווג החומר Classification of Matter מהו חומר? Matter is anything that has mass and occupies space. makes up the things we see everyday, such as water, wood, cooking pans, clothes, and shoes. can be classified as a pure substance or mixture. Mixture Matter Pure Substance

סיווג החומר Matter is organized by its components: elements, compounds, and mixtures.

חומרים טהורים Element – one Pure Substance A pure substance has a fixed or constant composition. can be classified as an element or compound. מהו חומר טהור? Element – one type of atom Pure Substance Compound – two or more elements chemically combined

חומרים טהורים: יסודות Elements are pure substances that contain atoms of only one type. Examples: copper (Cu) lead (Pb) aluminum (Al) מהו יסוד?

המשך: Element Cannot be separated chemically into simpler substances. Aluminum metal

חומרים טהורים: תרכובות Compounds contain two or more elements that are chemically combined in a definite ratio. Examples: salt (NaCl) table sugar (C12H22O11) water (H2O) מהי תרכובת?

התרכובת נתרן כלורי (מלח שולחני) Table salt is a compound that contains the elements sodium and chlorine. Can be separated chemically into simpler substances.

תערובות מהי תערובת? A mixture is matter that consists of two or more substances that are physically mixed, not chemically combined. a composition that is not constant. substances that can be separated by physical methods.

הפרדת מרכיבי התערובת (בבית) The physical separation of a mixture involves only physical changes. occurs when pasta and water are separated with a strainer.

הפרדת מרכיבי התערובת (במעבדה) The physical separation of a mixture in a chemistry lab may include: filtration chromatography

Types of Mixtures סוגי תערובות Homogeneous Mixture – Uniform Mixtures Mixtures are classified by their composition. called homogeneous when they are uniform. called heterogeneous when they are not uniform. Homogeneous Mixture – Uniform Mixtures Heterogeneous Mixture – Not uniform

הומוגנית תערובת In a homogeneous mixture, the מהי תערובת הומוגנית? composition is uniform throughout, and different parts of the mixture are not visible. מהי תערובת הומוגנית? פליז

הטרוגנית תערובת In a heterogeneous mixture, the composition is not uniform; it varies from one part of the mixture to another, and different parts of the mixture are visible. מהי תערובת הטרוגנית?

סיכום סיווג החומר Definite properties Properties depend on composition

1 תרגיל Learning Check Identify each of the following as a pure substance or a mixture. A. pasta and tomato sauce B. aluminum foil C. helium D. air

1 פתרון תרגיל Solution Identify each of the following as a pure substance or a mixture. A. pasta and tomato sauce mixture B. aluminum foil pure substance C. helium pure substance D. air mixture

2 תרגיל Learning Check Identify each of the following as a homogeneous or heterogeneous mixture. A. hot fudge sundae B. a clear shampoo C. sugar water D. peach pie

1 פתרון תרגיל Solution Identify each of the following as a homogeneous or heterogeneous mixture. A. hot fudge sundae heterogeneous mixture B. a clear shampoo homogeneous mixture C. sugar water homogeneous mixture D. peach pie heterogeneous mixture

הגדרת חומר, מסה, משקל Matter Mass Weight Anything that occupies space and has mass. Mass Measure of the amount of matter that an object contains. (unit – metric grams (g) ) Related to inertia – a tendency of a body at rest to be at rest Weight The effect of gravity on matter כֹּחַ הַהֶתְמֵד, אִינֶרְצְיָה