Question

5. Answer in one word or one sentence
i) Name the subatomic particles
2) What is never changed in a formula to balance an equation
3) on what basic is a chemical equation balanced
4) what type of changes is involved in the formation of from milk
5) what is the sum of protons and neutron know as
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Answer 1

Answer:

Even though chemical compounds are broken up and new compounds are formed during a chemical reaction, atoms in the reactants do not disappear, nor do new atoms appear to form the products. In chemical reactions, atoms are never created or destroyed. The same atoms that were present in the reactants are present in the products—they are merely reorganized into different arrangements. In a complete chemical equation, the two sides of the equation must be present on the reactant and the product sides of the equation.

Coefficients and Subscripts

There are two types of numbers that appear in chemical equations. There are subscripts, which are part of the chemical formulas of the reactants and products; and there are coefficients that are placed in front of the formulas to indicate how many molecules of that substance is used or produced.

Chemical equation: Cu + 2 AgNO3 makes Cu(NO3)2 + 2 Ag

Figure 7.4.1 : Balancing Equations. You cannot change subscripts in a chemical formula to balance a chemical equation; you can change only the coefficients. Changing subscripts changes the ratios of atoms in the molecule and the resulting chemical properties. For example, water (H2O) and hydrogen peroxide (H2O2) are chemically distinct substances. H2O2 decomposes to H2O and O2 gas when it comes in contact with the metal platinum, whereas no such reaction occurs between water and platinum.

Answer 2

Answer:

1. The three subatomic particles: protons, neutrons, and electrons
2. Subscripts are the smaller numbers found after atoms. These cannot be changed when balancing chemical equations
3. A Chemical equation is always balanced on comparison of number of atoms of each element on both sides of the reaction.
4. Chemical change is involved in the formation of curd from milk
5. Mass number refers to the sum of the number of protons and neutrons present in the nucleus of an atom and denoted by A