chemical reaction calculations
What is the number "4" in SiCl4?
a subscript
Akia is balancing the equation Na + H2O NaOH + H2. He tries to find the coefficients that will balance the equation. How could he find the correct coefficients?
by counting up each individual atom and make sure the atom numbers are the same in the reactants and the products
A(n) reaction is the rearrangement of atoms by breaking and reforming chemical bonds.
chemical
Kiley wants to balance the equation H2 + N2 → NH3. Which would be her first step in balancing an equation
creating a chart that shows the number of atoms in the reactants and products
The mole concept will most likely be used in
determining how many ozone molecules are lost in the atmosphere
Balanced chemical equations express the law of conservation of
mass
Which best represents the law of conservation of mass?
mass of reactants = mass of products
Which is an example of a chemical reaction?
paper burned and turned into smoke
Which of these most likely represents a chemical change
sugars digested by saliva
What is the molar mass of a substance?
the mass in grams of one mole of a substance
Cecil writes the equation for the reaction of hydrogen and oxygen below. H2 + O2 → H2O
to show that atoms are conserved in chemical reactions
What can the arrow in a chemical reaction be translated to mean? Check all that apply.
yields react to form
One half of a balanced chemical equation is shown. 3Mg(OH)2 + 2H3PO4 Which lists the numbers of each atom the other half of the equation would contain
3 Mg, 2 P, 14 O, 12 H
Substances A and B react in a ratio of A + B → AB. Colin was combining substance A and substance B to form substance AB. He added 10 g of substance A and 45 g of substance B. How much of substance AB would Colin make?
55g
How many chlorine atoms are on the products side of the reaction 2Al + 6HCl → 2AlCl3 + 3H2?
6
Which is the molar mass of BF3?
67.81 g/mol
Which are the products in the equation CH3SH + 4O2 → CO2 + SO2 +2H2O? Check all that apply.
CO2 SO2 H2O
Reggie and Charlotte are baking oatmeal cookies. They dip the baked cookies in melted chocolate. The chocolate cools to form a hardened coating. Reggie argues the entire chocolate-covered cookie has undergone a chemical change. Charlotte disagrees, saying only the original oatmeal cookie has undergone a chemical change, not the chocolate coating.
Charlotte, because baking causes a chemical change, but melting objects is a non-chemical change
Cherylanne mixes together Chemical A and Chemical B in a test tube, forming Chemical C. The mixture instantly turns cool to the touch. She then adds Chemical D, and the reaction becomes hot and explodes.
Chemicals A and B form an endothermic reaction, and chemicals C and D form an exothermic reaction
How are a mole and a dozen similar?
Each names a given number of objects
How does the number of molecules in 1 mol of oxygen compare with the number of molecules in 1 mol of nitrogen?
Each sample has the same number of molecules
Which is the correctly balanced equation for the reaction of rust, Fe2O3, and hydrochloric acid, HCl?
Fe2O3 + 6 HCl → 2 FeCl3 + 3 H2O
Potassium chlorate decomposes to produce 20 g of solid potassium chloride. Oxygen gas is also produced. Which best describes the mass of oxygen
It is less than the mass of potassium chlorate
Chemical A and Chemical B react in an exothermic reaction. What can be known about what will happen when Chemical A and Chemical B are mixed together?
More energy will be released from the old substance than the new substance will need to form its chemical bonds
Pedro wants to create a chemical reaction between oil and water. He adds oil to a beaker of water and notices that the liquids do not mix. He then shakes the beaker and the drops of oil become suspended through the water for a few moments before returning to their separate layers.
No, because no new substances were formed
Which best describes the law of conservation of mass?
The mass of the reactants and products is equal and is not dependent on the physical state of the substances
Two chemicals react in an endothermic reaction. What can be known about this reaction?
The new substance will need more energy to form its chemical bonds than the old substance will release.
Consider the equation below. Na+ + Cl- mc013-1.jpg NaCl Which statement best describes the relationship between the substances in the equation?
The number of sodium ions is equal to the number of formula units of salt
Magnesium and iron are metallic elements. How does a mole of magnesium compare with a mole of iron?
They both have the same number of atoms
Which is the balanced equation for V2O5 + CaS → CaO + V2S5?
V2O5 + 5CaS → 5CaO + V2S5
Leslie incorrectly balances an equation as 2C4H10 + 12O2 → 8CO2 + 10H2O.
12
Which is the formula mass of (NH4)2SO4
132.17 amu
Which is the molar mass of H2O?
18.02 g/mol
The equations are not balanced. Which equation would have the same coefficients in the same order as 2CO2 + 3H20 → C2H6O + 3O2?
Al + FeO → Al2O3 + Fe