Science Quizzes Solution Sets

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O = 2 x4 + 15x2 =38 O = 12 x 2 + 14 = 38

4) b. 2 HCN + NO2 → C2N2 + NO + H2O

H = 2 H = 2

C = 2 C = 2

N = 3 N = 3

O = 2 O = 2

- a. ionic bond refers to the electrostatic attraction between positive( cation) and negative (anion) ions.

- D) mass number = neutron number plus proton number = 74 + 53 = 127

- a. proton # = atomic number = 53

- a. in a neutral atom, the number of electron is also equal to the number of protons = 53

- d. double replacement reaction. Fe replaces Na and Cl replaces PO4.

- B. Calcium carbonate decomposes into CaO and carbon dioxide

- A. Mg combines with nitrogen to produce magnesim nitride.

- C. Zinc replaces hydrogen.

- Given

M1 = 3M V1 = 3L

M2 = 6M V2 = ?

M1 V1 = M2 V2 [pic 3] [pic 4]

- Given

Moles of Hydrogen = ?

2.5 moles N2

Stoic Ratio : 1 N2 = 3 H2

Moles of H2 = 2.5 mol N2 x [pic 5]= 7.5 mol H2

- From no. 14, 7.5 mol Hydrogen is produced

7.5 mol H2 x [pic 6]= 15 g H2

- Given:

V1 = 450 mL V2 = ?

T1 = 30 C T2 = 50 C

V2 = [pic 7]

- Solution is the mixture that particles don not settle down, cannot be filtered, and cannot be seen by the naked eye.

- From the combined gas law, pressure is inversely proportional to the volume and is directly proportional to the temperature. If the temperature is decreased, the pressure also decreases inside a container.

- According to Boyle’s law, at constant temperature, the volume of a gas is inversely proportional to the amount of pressure exerted on it. If the pressure is doubled, volume will decrease.

- The formula that indicates the local number of atoms of the elements un a compound is the empirical formula.

- The reaction between magnesium chloride and potassium hydroxide is a double replacement reaction that produces Mg(OH)2 and KCl.

- Orbitals (s, p, d, f) make up subshell (2s, 2p, 2d, 2f), subshells make up the shell (energy levels 1, 2, 3,…7)

- Molarity, molality, and normality are all modes of expressing concentration of solutions. Acidity is the measure of alkalinity of solutions.

- Based on the law of mass conservation,if 50 g of the reactants is used up in a reaction, 50g of the products will be produced.

- Freezing carbon dioxide does not involve change in chemical composition and formation of new peoducts. Therefore, it is physical reaction.

- Atomic number is equal to the number of protons. Mass num,ber is equal to the number of protons plus the number of neutrons.

- In a compound, the sum of the total positive oxidation numbers and negative oxidation numbers must be equal to zero.

- Atoms of the same elements having the same atomic number can have different mass number due to differences in their number of neutrons. These atoms are called isotopes.

- Random movement of particles is least observable in solids. The particles are compactly arranged in solids.

- Electrons found in an incomplete outer shell of an atom are called valence electrons.

PHYSICS

- A vector is a quantity with both magnitude and direction. Displacement, force, and acceleration are all vector quantities except speed.

- Mmmm

- 1 N is defined to be 1 kg m/s2. Force = weight (gravity due to acceleration= 10m/s2)

- Illustration: [pic 8]

a = 0.5 km

b= 1.2 km

c = ?

c = [pic 9]

c = 1.3

- a = ΔV / Δt = 20 m/s / 5 s = 4 m/s2

- a = force / mass

Given : m = 2 kg a = 0.5 m/s2

F = mass x acceleration

F = 2 kg x 0.5 m/s2 = 1 kg m/s2 = 1 N

- xxxxx

- Kinematics is the study under dynamics that deals with the space-time relationship in bodies that are in motion.

- Centripetal force = [pic 10][pic 11]

Given: mass = 100 kg, radius = 60 meters, v = 30 m/s

[pic 12][pic 13]

- In baseball, if the action is the impact of the bat against the ball, the opposite reaction is the force of the ball against the bat. This satisfies the law of action and reaction.

- Boni

- Instantaneous speed is defined as the quantitative measure of the change of an object’s position over a certain amount of time.

- Projectile motion is defined as the movement of body launched in space without its motive power, and travels freely under the action of gravity and air resistance alone.

- At rest, the distance (meters) is constant, time (seconds) varries. (c)

- An increase in temperature and distance illutrates a car traveling at constant velocity. (b)

- xxxx

- xxxx

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