Welcome to your Chemical Formulae and Chemical Equations (STUDY BY TOPICS JUNIOR CLASS) NAME EMAIL PHONE NUMBER 1. Which one of the following is not a physical change? Making toast Mixing salt and pepper Melting chocolate Cutting a page in half 2. An example of mixture is fruit salad rust salt oxygen 3. The components elements of soap are water, sodium, oxygen and hydrogen calcium, carbon and oxygen silicon and oxygen sodium, oxygen, carbon and hydrogen carbon, hydrogen and oxygen 4. If two liquids are mutually soluble, they are called _______ liquids. Miscible Insoluble Soluble Immiscible 5. Which of the following factors does NOT affect the rate of a chemical reaction? Colour of the reactants Number of particles reacting Temperature of the reactants Size of the reactants 6. Fill in the blanks:_______ cannot be created or destroyed, but can be __________ from one form to another. Matter, produced Matter, changed Liquids, changed Gases, sent 7. When iron rusts, the kind of change that takes place is mixture physical chemical state 8. CaO- calcium Oxide reaction with water is regarded as exothermic. A student mixes these two products in a test tube and touches its side surface. Which of the following statement correctly describes the student's observation? The test tube becomes cold due to release of heat energy The test tube becomes hot due to absorption of heat energy The test tube becomes cold due to absorption of heat energy The test tube becomes hot due to release of heat energy 9. Aluminum reacts with copper sulphate to produce Cu, Al2S3 and SO2 Cu and Al2(SO4)3 CuO and Al2(SO4)3 CuO, Al2S3 and SO2 10. Which of the following is a chemical change? Melting Burning Contracting Freezing 11. Adding sugar to a cup of tea is a physical change because it is possible to separate the sugar from the tea the tea tastes sweeter there is no change in colour there is no change in temperature 12. In a chemical reaction, the substances that react together are called the processes the reactants the chemicals the products 13. Respiration is an important chemical reaction that takes place in plants and animals. This process may be represented by a chemical equation. Fill in the blanks in this equation: Glucose + Oxygen → _______ + _________ Water + Nitrogen Air + Water Carbon dioxide + Air Carbon dioxide + Water 14. What is chemical formula? Tells the number of atoms in chemical reaction A chemical symbol that has symbol Tells the number of atoms of each element a compound. Subscrpit tells number of element in a molecues All Above 15. You can tell a chemical reaction because it always produces … Water Reactants A change of state A different substance 16. What is the LAW of Conservation of Mass? Cannot be created or destroy Can destroy or create Chemical equations Chemical equation must be balanced because matter cannot be created or destoryed. 17. A true solution is a homogeneous mixture of solute and solvent. Chalk powder in water is a heterogenous mixture. Is it a true solution? Yes. it is a true solution. No. it is not a true solution. It is called Colloid. No. it is not a true solution. It is called Suspension No. it is a true solution. 18. What happens when dilute HCl is added to iron filings? No reaction takes place. Chlorine gas and iron hydroxide are produced. Iron salt and water are produced. Hydrogen gas and iron chloride are produced. 19. The reaction where water is chemically broken down by passing an electric current through it, is called electronic endothermic exothermic electrolysis 20. What kind of reaction occurs when the negative ions in 2 compounds switch? Decomposition Double-replacement Combustion Synthesis 1 out of 20 Time is Up! Time's up
