Question

What is the only SI base unit that includes a prefix?

(a) meter (b)
kelvin (c)
kilogram (d)
mole (e) second

Which is the highest temperature among the following
temperatures?

(a) 85 K (b)
75OC (c)
115oF (d) 125 K

Express the number, 1292.5 x 10-17, in scientific notation.

(a) 12.925 x 10-14 (b) 1.2925
x 10-14 (c) 1.2925 x 10-15 (d)
1.2925 x 10-13

In which of the following pairs do both

Which numbers have three significant figures?

(i) 0.0500 (ii) 0.050
(iii) 5.00 (iv) 50.0 (v) 0.005

(a) i, iii,v (b)
i,iii,iv (c) ii, iii, iv (d)
iii,iv,v

The mass of a sample of iron metal is 5.932 g. If the density of
iron is 7.8 g/cm3, what is its

volume?

1.31 cm3 (b) 1.3 cm3 (c)
0.76 cm3 (d) 0.761 cm3

What is the sum of 23.45 km, 104.1 km, and 0.025 km?

(a) 127.6 km (b) 127.56 km (c) 127.575
km (d) 127 km

Express the following calculation to the proper number of
significant figures.

(1.36 x 10-6)(0.4) / (5.6) .

(a).0964 x 10-6 (b) .1 x 10-6 (c) .096 x 10-6
(d) .09 x 10-6

The mass of an object is 100.0 lb. What is its mass in
grams?

(a) 4.536 x 103 (b) 4.536 x
104 (c) 4.536 x 105 (d) 4.536 x
102

Perform the following calculations and express each answer to
appropriate number of

significant figures.

0.1357 + 0.12 – 0.037 (b) 0.458 x
16.80 x 0.096

(c) 432.7 x 6.5 x 0.0023 / 62 x 0.103 (d)
32.44 + 4.9 – 0.304 / 82.94

Express each of the following numbers in scientific
notation:

(a) 32540 (b) 0.00001234 (c) 331.12 x
105 (d) 22.23 x 10-11

.Balance the following equations. For these equations, all
coefficients must be whole numbers.

(a)
Al(s)
+
HCl(aq)
→ AlCl3(aq)
+ H2(g)

(b)
NaN3(s)
→
Na(s)
+ N2(g)

(c) Pb(NO3)2(aq)
+
KCl(aq)
→ PbCl2(s)
+ KNO3(aq)

(d)
C2H6(g)
+
O2(g)
→
CO2(g)
+ H2O(l)

(e)
Fe2O3(s)
+
C(S)
→ Fe(s)
+ CO(g)

Answer #1

Calculate the standard enthalpy change, ΔH°rxn, in kJ for the
following chemical equation, using only the thermochemical
equations below: 4KO2(s) + 2H2O(l) → 4KOH(aq) + 3O2(g) Report your
answer to three significant figures in scientific notation.
Equations: ΔH°rxn
(kJ)
4K(s) + O2(g) → 2K2O(s)
-726.4
K(s) + O2(g) → KO2(s) -284.5
K2O(s) + H2O(l) → 2KOH(aq) -318

Part A
Initially, only A and B are present, each at 2.00 mol L−1. What
is the final concentration of A once equilibrium is reached?
Express your answer to two significant figures and include the
appropriate units.
The reversible chemical reaction
A(aq)+B(aq)⇌C(aq)+D(aq)
Part B
What is the final concentration of Dat equilibrium if the
initial concentrations are [A] = 1.00 mol L−1 and [B] = 2.00 mol
L−1 ?
Express your answer to two significant figures and include the
appropriate...

Mass of a Moving Particle The mass m of a particle moving at a
velocity v is related to its rest mass m0 by the equation m = m0 1
− v2 c2 where c (2.98 ✕ 108 m/s) is the speed of light. Suppose an
electron of rest mass 9.11 ✕ 10−31 kg is being accelerated in a
particle accelerator. When its velocity is 2.84 ✕ 108 m/s and its
acceleration is 2.49 ✕ 105 m/s2, how fast is...

1)
A Cu/Cu2+ concentration cell has
a voltage of 0.21 V at 25 ∘C. The concentration of Cu2+ in one of
the half-cells is 1.5×10−3 M .
What is the concentration of Cu2+ in the other half-cell?
Express your answer using two significant figures.
2)
Galvanized nails are iron nails that have been plated with zinc
to prevent rusting. The relevant reaction is
Zn2+(aq)+2e−→Zn(s)
For a large batch of nails, a manufacturer needs to plate a
total zinc mass of...

« previous 21 of 25 next »
Calculate the molar mass for each of the following:
Part A
ZnSO4, zinc sulfate, zinc supplement.
Express your answer using five significant figures.
M1 =
g/mol
Part B
C12H24O2, lauric acid, from coconut oil
Express your answer using five significant figures.
M2 =
g/mol
Part C
FeSO4, ferrous sulfate, iron supplement.
Express your answer using five significant figures.
M3 =
g/mol
Part D
Ca3(C6H5O7)2, calcium citrate, calcium supplement
Express your answer using five...

Part B
What is the final concentration of Dat equilibrium if the
initial concentrations are [A] = 1.00 mol L−1 and [B] = 2.00 mol
L−1 ?
Express your answer to two significant figures and include the
appropriate units.
The reversible chemical reaction
A(aq)+B(aq)⇌C(aq)+D(aq)
has the following equilibrium constant:
K=[C][D][A][B]=2.5
Part A
Initially, only A and B are present, each at 2.00 mol L−1. What
is the final concentration of A once equilibrium is reached?
Express your answer to two...

Express the following quantities in without prefixes and in
scientific notation:
(a) 0.000325 kg, (b) 15090 g, (c) 2000 µs, (d) 4.1×10−8 GHz, (e)
2.7×108 MB

Iron(III) oxide reacts with carbon to give iron and carbon
monoxide.
Fe2O3(s)+3C(s)→2Fe(s)+3CO(g)
Part A: How many grams of C are required to react with 19.9 g of
Fe2O3?
Part B: How many grams of CO are produced when 37.0 g of C
reacts?
Part C: How many grams of Fe can be produced when 5.60 g of
Fe2O3 reacts?
2. How many moles of S are in each of the following
quantities?
Part A: 21 g of S (Express your...

1. A constant electric current flows for 3.35 h through
electrolytic cells connected in series. One contains a solution of
AgNO3, and the second contains a solution of
CuCl2. During this time, 1.80 g of silver is deposited
in the first cell.
(a) How many grams of copper are deposited in the second
cell?
g Cu
(b) What is the current flowing in (in amperes) ?
A
2. Oxalic acid (H2C2O4) is
present in many plants and vegetables.
(a) Balance...

Part A
A copper pot of mass 2.5 kg contains 5.2 litres of water (i.e.
5.2 kg) at room temperature (200C). An iron block of
mass 9.4 kg is dropped into the water and when the system comes
into thermal equilibrium, a temperature of 380C is
measured. What is the initial temperature of the iron block? Give
your answer in oC to three significant figures.
Part B
Iron has a specific heat that is larger than that of copper. A...

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