Answer:
Chemical reaction involves the breaking of bonds in the reactants and formation of bonds in the products. ... If a reaction is exothermic, more energy is released when the bonds of the products are formed than it takes to break the bonds of the reactants. This is the reason for temperature change during a reaction.
Explanation:
Here are just a few everyday demonstrations that temperature changes the rate of chemical reaction: Cookies bake faster at higher temperatures. Bread dough rises more quickly in a warm place than in a cool one.
Answer:
Explanation:
When you are in the laboratory and take a direct sniff of the chemicals you are using, you run the risk of damaging your mucous membranes or your lungs. When it is necessary to smell chemicals in the lab, the proper technique is to cup your hand above the container and waft the air toward your face.
Answer:
6.00%
Explanation:
Step 1: Given data
Accepted value for the number of calories in a Bananas Foster: 300 calories
Measured value for the number of calories in a Bananas Foster: 318 calories
Step 2: Calculate the percent error in the measure
We will use the following expression.
%error = |accepted value - experimental value|/ accepted value × 100%
%error = |300 cal - 318 cal|/ 300 cal × 100% = 6.00%
Answer:
AS we move from bottom to top on periodic table shielding decreased.
Explanation:
As we move from left to right across the periodic table the number of valance electrons in an atom increase. The atomic size tend to decrease in same period of periodic table because the electrons are added with in the same shell. When the electron are added, at the same time protons are also added in the nucleus. The positive charge is going to increase and this charge is greater in effect than the charge of electrons. This effect lead to the greater nuclear attraction.
As we move down the group atomic radii increased with increase of atomic number. The addition of electron in next level cause the atomic radii to increased. The hold of nucleus on valance shell become weaker because of shielding of electrons thus size of atom increased.
As we move from bottom to top the energy level decreased because of decreased in electron thus shielding decreased and atomic size also decreased.
Every isotope of an element has a different number of neutrons, which means that the atomic property which is different in each isotope of an element is mass number.
Mass number depends on the number of neutrons in an element.
