Chem u5
What is the oxidation number of chromium in K2Cr2O7
+6
What is produced in a double-displacement reaction?
2 new compounds
Which equation is the balanced equation for Ca + O2→CaO ?
2Ca + O2→2CaO
Which equation represents the balanced chemical equation for the synthesis reaction that forms magnesium oxide (MgO) ?
2Mg + O2→2MgO
Which equation is balanced? 2Na + Cl2→2NaCl 2Na + Cl2→NaCl Na + Cl2→NaCl Na + 2Cl2→2NaCl
2Na + Cl2→2NaCl
Which equation represents a combustion reaction? 2AgNO3 + H2S→Ag2S + 2NHO3 2Al + N2→2AlN 2H2O →2H2+O2 4Fe + 3O2→2Fe2O3
4Fe + 3O2→2Fe2O3
Which reaction is an example of a synthesis reaction?
4H+O2→2H2O
What is the balanced equation for P + O2→P2O5 ?
4P + 5O2→2P2O5
The equation 2NaNO3 + CaCl2→2NaCl + Ca(NO3)2 is balanced.How many atoms of oxygen are there on each side of the equation?
6
Which equation represents a decomposition reaction?
6NaNO3→6NaNO2+3O2
Which generalized equation best represents a combustion reaction?
A + oxygen→energy
What is the general equation for a double-displacement reaction?
AX + BY→AY +BX
A piece of copper is placed into silver nitrate. Given that the activity of copper is greater than that of silver, what will happen?
Copper will replace silver to form copper nitrate, because the activity of copper is greater than that of silver.
What are the products of a single-displacement reaction when magnesium metal (Mg) reacts with copper sulfate (CuSO4) ?
Cu + MgSO4
most active to least active elements
Li, K, Ba, Sr, Ca, Na, Mg, Al, Mn, Zn, Fe, Cd, Co, Ni, Sn, Pb,H,Cu, Ag, Hg, Au
Which equation represents a neutralization reaction?
NaOH (aq) + HCl (aq)→NaCl (aq)+H2O (I)
What is always true of a single-displacement reaction?
One element replaces another element in a compound.
Which equation is the balanced chemical equation for the synthesis reaction for the formation of sulfur dioxide (SO2) ?
S + O2→SO2
Why is Cl2 + KI→ KCl +I2 not a synthesis reaction?
The reaction has more than one product.
Consider this reaction: 2HgO→2Hg + O2 .
This is a decomposition reaction because there is only one reactant.
Will lead (Pb) react with HgSO4 ?
Yes, a reaction will occur because the activity of lead is greater than that of mercury.
What is most often necessary for a decomposition reaction to occur?
addition of energy
Which phrase is not likely to indicate that a double-displacement reaction has occurred?
change of a metal ion to a metal element
CaCO3 + 2HCl→CaCl2+H2CO3 is an example of which type of reaction?
double displacement
reduction
gain of electrons by an atom
When wood burns in the presences of oxygen, in what form is energy released?
heat n light
Most of the substances we use for fuel are hydrocarbons that burn easily in the presence of oxygen. Which two elements are found in these substances?
hydrogen n carbon
What would most likely be the products of the decomposition of HI (hydrogen iodide) ?
hydrogen n iodine
oxidation
loss of electrons by an atom
What must methane be combined with to undergo a combustion reaction?
oxygen
Which reaction is the opposite of a decomposition reaction?
synthesis
Which statement is true about synthesis reactions?
they must have two or more reactants.
Why must chemical equations be balanced?
to represent conservation of mass
