Chemicals Interactions - PVM_7

The positively charged particles in the nucleus of an atom are called __________________.

• electrons

• ions

• neutrons

• protons

A change in matter that produces a new substance is called a _____________________.

• chemical reaction.

• physical change.

• mixture.

• solution.

Which of the following is an example of a physical property?

• chemical composition

• ability to burn

• freezing point

• ability to react with metals

A chemical reaction in which energy is absorbed in the form of heat is called __________________.

• synthetic

• exothermic

• combustion

• endothermic

Chemical equations must be balanced because chemical reactions obey the principle of _________________________.

• activation

• conservation of mass

• decomposition

• mass coefficients

Most inhibitors work by preventing ________________.

• reactants from coming together.

• enzymes from working.

• products from forming.

• combustion.

When two or more substances combine to form a more complex substance, the process is called a ______________.

• decomposition reaction

• replacement reaction

• synthesis reaction

• physical change

The number in front of a chemical formula that tells how many molecules or atoms of each reactant take part in a reaction is called a ___________________.

• symbol

• subscript

• coefficient

• concentration

Which of the following is an example of a chemical change?

• meat spoiling

• water freezing

• mercury rising

• butter softening

Which statement is true about an exothermic reaction?

• It releases energy.

• It absorbs energy.

• It requires no activation energy.

• The energy of the products is greater than the energy of the reactants.