Chemistry

 Fill in the blanks  1. All organisms, or living things, are made of-------.  Cells 2. A single-celled organism that can carry on all its life processes is called---------------------------.  Unicellular 3. Organisms made up of more than one cell are called-------------------------------.  Multicellular 4. Both plant and animal cells perform life processes by using---------------------------------.  Organelles  5. All cells are surrounded by a(n)---------------------- that controls the materials that move in and out of the cell.  Cell membrane 6. The cell's control center is called the--------------------.  Nucleus 7. A structure in a cell used for storage of water, food, and waste is the-------------------------------------.  Vacuoles 8. A green structure, called a(n)---------------------; uses the energy from the Sun to produce food for the plant.  Chloroplast  9 . Cells working together at the same job form a(n)-------------...

Dynamic equilibrium: Many reactions are one-way only'. The starting materials react to form the products. The products can't easily be turned back into the starting materials again. Imagine trying to turn a cake back into flour, sugar, butter and eggs. In a 'closed system' both the forward and reverse reactions will be going at the same rate.  When this happens it is called dynamic equilibrium. What the word 'dynamic' means? Dynamic' refers to movement. People who have lots of energy and are always on the move. At equilibrium, the rate of the forward reaction and the reverse reaction is the same. When equilibrium is reached, the amount of each substance stays the same.

Metals, non metals and semi-metal  Group s 1 and 2 are all metal s, whe r e a s Groups 7 a n d 0 contain only non - metals . E l e m e nts i n th e midd l e groups s tart w i t h non-m e ta l s at t h e top , bu t fini s h wit h m e ta l s  at t h e bottom . S ili con i s t h e m os t w e ll - known sem i - metal. It b e h av e s li k e a meta l i n some way s ,  bu t li ke a n on - m e tal i n oth e rs . What are metals? A solid material which is typically hard, shiny, malleable, fusible, and ductile, with good electrical and thermal conductivity. What are non-metals? Element or substance that is not a metal. M ostly lacks the characteristics of a metal. What are semi-metals? Element whose properties are intermediate between those of metals and non-metals.

Reversible reactions: Have you ever seen a toothbrush that changes colour as you use it? Changes which can go backwards or forwards are called reversible. When you heat blue (hydrated) copper sulfate, it loses the water which is bonded in its crystals. This reaction is called dehydration. It is endothermic. You get a white powder called anhydrous copper sulfate. If you add water, the blue (hydrated) copper sulfate is formed again. This is called hydration. It is exothermic. Reversible reactions are shown by arrows pointing in both directions : hydrated copper sulfate  ↔  anhydrous copper sulfate + water (blue crystals)                                  (white powder) CuS04 .5 H20  ↔  CuS04 + 5 H 2O The energy absorbed in the forward reaction is the same as the energy given out in the reverse reaction. Q: What is reversible reactions? Ans: Changes which can go backwards or forwards are...

  What are Groups & Periods in periodic table? 

Define fertilization  A sperm cell from a male and an egg cell from a female  join into a single unit in a process called fertilization.

Differentiate between sexual and asexual  reproduction? Sexual Reproduction: Sexual reproduction is the production of a new organism from two parents. Asexual Reproduction: Asexual reproduction is the production of a new organism from a single parent. Differentiate between sexual and asexual  reproduction: