Write balanced equations for each of the following reactions:
Lead (II) nitrate solution reacts with potassium iodide solution.
When heated, aluminium reacts with solid copper oxide to produce copper metal and aluminium oxide (
).
When calcium chloride solution is mixed with silver nitrate solution, a white precipitate (solid) of silver chloride appears. Calcium nitrate (
) is also produced in the solution.
Balanced equations are very important in chemistry. It is only by working with the balanced equations that chemists can perform many different calculations that tell them what quantity of something reacts. In a later chapter we will learn how to work with some of these calculations. We can interpret balanced chemical equations in terms of the conservation of matter, the conservation of mass or the conservation of energy.
Summary
A
chemical equation uses symbols to describe a chemical reaction.
In a chemical equation,
reactants are written on the left hand side of the equation and the
products on the right. The arrow is used to show the direction of the reaction.
When representing chemical change, it is important to be able to write the
chemical formula of a compound.
In any chemical reaction, the
law of conservation of mass applies. This means that the total atomic mass of the reactants must be the same as the total atomic mass of the products. This also means that the number of atoms of each element in the reactants must be the same as the number of atoms of each element in the product.
If the number of atoms of each element in the reactants is the same as the number of atoms of each element in the product, then the equation is
balanced .
If the number of atoms of each element in the reactants is not the same as the number of atoms of each element in the product, then the equation is
not balanced .
In order to balance an equation,
coefficients can be placed in front of the reactants and products until the number of atoms of each element is the same on both sides of the equation.
End of chapter exercises
Propane is a fuel that is commonly used as a heat source for engines and homes. Balance the following equation for the combustion of propane:
Aspartame, an artificial sweetener, has the formula
. Write the balanced equation for its combustion (reaction with
) to form
gas, liquid
, and
gas.
Chemical weapons were banned by the Geneva Protocol in 1925. According to this protocol, all chemicals that release suffocating and poisonous gases are not to be used as weapons. White phosphorus, a very reactive allotrope of phosphorus, was recently used during a military attack. Phosphorus burns vigorously in oxygen. Many people got severe burns and some died as a result. The equation for this spontaneous reaction is:
Balance the chemical equation.
Prove that the law of conservation of mass is obeyed during this chemical reaction.
Name the product formed during this reaction.
Classify the reaction as endothermic or exothermic. Give a reason for your answer.
Classify the reaction as a synthesis or decomposition reaction. Give a reason for your answer.
(DoE Exemplar Paper 2 2007)
Mixing bleach (
) and ammonia (two common household cleaners) is very dangerous. When these two substances are mixed they produce toxic chloaramine (
) fumes. Balance the following equations that occur when bleach and ammonia are mixed:
If there is more bleach than ammonia the following may occur:
Nitrogen trichloride (
) is highly explosive.
If there is more ammonia than bleach the following may occur:
These two products then react with ammonia as follows:
One last reaction occurs to stabilise the hydrazine and chloramine:
This reaction is highly exothermic and will explode.
Balance the following chemical equation:
Sulphur can be produced by the Claus process. This two-step process involves reacting hydrogen sulphide with oxygen and then reacting the sulphur dioxide that is produced with more hydrogen sulphide. The equations for these two reactions are:
Balance these two equations.
Questions & Answers
A golfer on a fairway is 70 m away from the green, which sits below the level of the fairway by 20 m. If the golfer hits the ball at an angle of 40° with an initial speed of 20 m/s, how close to the green does she come?
A mouse of mass 200 g falls 100 m down a vertical mine shaft and lands at the bottom with a speed of 8.0 m/s. During its fall, how much work is done on the mouse by air resistance
Chemistry is a branch of science that deals with the study of matter,it composition,it structure and the changes it undergoes
Adjei
please, I'm a physics student and I need help in physics
Adjanou
chemistry could also be understood like the sexual attraction/repulsion of the male and female elements. the reaction varies depending on the energy differences of each given gender. + masculine -female.
Pedro
A ball is thrown straight up.it passes a 2.0m high window 7.50 m off the ground on it path up and takes 1.30 s to go past the window.what was the ball initial velocity
2. A sled plus passenger with total mass 50 kg is pulled 20 m across the snow (0.20) at constant velocity by a force directed 25° above the horizontal. Calculate (a) the work of the applied force, (b) the work of friction, and (c) the total work.
you have been hired as an espert witness in a court case involving an automobile accident. the accident involved car A of mass 1500kg which crashed into stationary car B of mass 1100kg. the driver of car A applied his brakes 15 m before he skidded and crashed into car B. after the collision, car A s
can someone explain to me, an ignorant high school student, why the trend of the graph doesn't follow the fact that the higher frequency a sound wave is, the more power it is, hence, making me think the phons output would follow this general trend?
Nevermind i just realied that the graph is the phons output for a person with normal hearing and not just the phons output of the sound waves power, I should read the entire thing next time
Joseph
Follow up question, does anyone know where I can find a graph that accuretly depicts the actual relative "power" output of sound over its frequency instead of just humans hearing
Joseph
"Generation of electrical energy from sound energy | IEEE Conference Publication | IEEE Xplore" ***ieeexplore.ieee.org/document/7150687?reload=true
A string is 3.00 m long with a mass of 5.00 g. The string is held taut with a tension of 500.00 N applied to the string. A pulse is sent down the string. How long does it take the pulse to travel the 3.00 m of the string?