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Science Test Review
- The positively-charged, subatomic particle is a proton.
- The nucleus is the positively charges central core of an atom.
- The space around the nucleus of an atom where the atom’s electrons are found is called the electron cloud.
- The number of protons in the nucleus of an atom of an element is the atomic number of that element.
- A fact of nature that has been confirmed many times by observation is known as a scientific law.
- The sum of the protons and neutrons in the nucleus of an atom is called the mass number of that atom.
- A negatively charged particle found in all atoms is the electron.
- In science, a testable prediction to explain observations is known as a hypothesis.
- The smallest particle of which matter consists is an atom.
- What is the atomic mass of hafnium if, out of every 100 atoms, 5 have mass 176, 19 have mass 177, 27 have mass 178, 14 have mass 179, and 35 have mass 180.0?
Multiply : 5 x 176 =
9 x 177
27 x 178 =
14 x 179 =
35 x 180.0 =
Add all of them together and ten divide by 100
- An atom of tin has atomic number of 50 and mass number of 119. How many protons, neutrons, and electrons does this atom of tin contain? Protons - 50, electrons - 50, Neutrons - 69
- What 2 factors determine the location of an electron around the nucleus? Attraction for nucleus and speed or energy of electron.
- sequence the following parts of a scientific method: experiment, hypothesis, observation, revised hypothesis, theory. Observation, hypothesis, experiment, revised hypothesis, and theory.
-According to the law of conservation of matter, if 4.0 g of hydrogen react with chlorine to produce 146 g of hydrogen chloride, how many grams of chlorine reacted? 142 g
- If 9.0 g of water contain 1.0 g of hydrogen, what mass of oxygen is contained in 36 g of water?
32 g
- The alloy brass is made from copper and zinc. Brass is an element.
- What is a good comparison of the charge of an electron and the charge of a proton? They are equal, but opposite
- Democritus first proposed that matter is made up of atoms, the smallest particles of matter.
- Coal burns in a furnace, producing light and heat. This reaction is exothermic.
-Sugar, which is a substance, can be broken down into carbon, oxygen, and hydrogen. Sugar is a compound.
- A 26.0-g sample of a liquid was found to have a volume of 13.0 mL. What is the density of the liquid? 2.00 g/mL
- A physical property of zinc metal is its color.
- In a list of the densities of common materials, the one density that might not seem reasonable is 35 885 g/mL
- An example of a chemical formula is H2SO4.
- The mass number of an element whose atoms have 12 protons and 13 neutrons is 25.
- J.J. Thomson used a cathode ray to discover the electron.
- The atomic number of an element whose atoms have 9 protons and 10 neutrons is 9.
- In a Lewis dot diagram, the dots represent the valence electrons in the atom.
- The best way to understand the submicroscopic world is with models.
- Which of the following materials cannot be broken down into a simpler form? Element
- Which of the following statements is not a main point of Dalton’s atomic theory? Atoms are made up of smaller particles
- When ice melts and becomes liquid water, it has undergone a physical change.
- The scientific statement that says that compounds always have exactly the same composition by mass is the law of definite proportion.
- An example of a chemical change is burning.
- The structure of matter refers to its composition.
- Atomic mass units are based on the mass of an atom of carbon-12.
- One isotope of carbon has 6 protons and 6 neutrons. The number of protons and neutrons of a second isotope of carbon would be 6 and 7.
- Liquid chlorine bleach breaks down into other substances when exposed to light. The instability of bleach is a chemical change.
- When a hypothesis is tested by many experiments, it becomes a theory.
- The experimentation of Rutherford led to the theory that the atom is a sphere of mostly empty space, with a positively charged nucleus with electrons around it.
- Gold melts at 1064̊C. Melting point is a physical property.
- The electron cloud is where the electron is most likely to be found.
- The only subatomic particle that does not carry an electric charge is the neutron.
- Iodine-131 and iodine-127 are examples of isotopes.
- The density of a material depends on its mass and volume.
- Matter on the atomic level is submicroscopic.
- Classification based on measurements is said to be quantitative.
- Which of the following liquids is most volatile? Alcohol