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Description
Flashcards by Ahmed Almohammed, updated more than 1 year ago
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Created by Ahmed Almohammed
over 8 years ago
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| Question | Answer |
| What are compounds? | Substances made of lattices or identical molecules of two or more types of atoms. |
| What is the similarity between compounds and elements? | Elements and compounds have unique sets of properties. |
| How can scientists develop useful materials such as perfumes and plastic? | By understanding how the elements combine to form new substances. |
| The human body is made up of just 16 elements.However, 98.5% of the body is made up of just six. What are they? | Oxygen(65%) Carbon(18%) Hydrogen(10%) Nitrogen(3%) Calcium(1.5%) Phosophorus(1%) |
| How are the molecules shaped in compounds? | The molecules in many compounds are small and contain just a few atoms.However,all the molecules in any compound are all identical in size, shape and a number of atoms. |
| How do scientists represent the molecules of compounds? | Similar to the molecules of elements, molecules of compounds are represented by a molecular formula such as H*2*O |
| Describe the atoms in compound lattices. | In lattices, the atoms are bonded very strongly to each other so they tend to be very hard solids at room temperature. |
| What does NaCl tell you? (Table salt) | From this formula, you can tell see that table salt is made up from sodium(Na) and chlorine(Cl). |
| What does this chemical formula indicate? ----------->SiO2<--------- (Beach sand) | It indicates that in a grain of beach sand, there is one silicon atom for every two oxygen atom. |
| What are mixtures? | Any combinations of two or more elements and compounds |
| How is air a mixture? | Air is a mixture because it is a mixture of oxygen,nitrogen,water vapour,carbon dioxide and carbon monoxide. |
| Why isn't there any chemical formula for mixtures? | It is because the molecules in mixtures are not identical. |
| Why is it that any two gases are easily mixed together? | Any two gases are easily mixed together because the particles of a gas are separated by large distance. |
| What is it referred to when small liquid particles are mixed into a gas? | Smoke or dust |
| What is the difference between miscible and immiscible? | Liquids that can be mixed are said to be miscible while liquids that don't mix are said to be immiscible. |
| What happens when gasses are mixed into liquids? | They may dissolve to form a solution or the gases may remain within the liquid as bubbles. In this case, the mixture is called a foam. |
| What is a colloid? | A colloid is a mixture where at least two types of substances are placed together |
| What is a suspension? | A suspension is a mixture of a liquid and particles of a solid. In this case, the particles do not dissolve. |
| What are alloys? | Alloys are a mixture of a metal with other metals or non-metals. |
| Why are alloys important? | Alloys are important because they often have very different and useful properties compared to the pure metal. |
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