Download Chem Chapter 1 Homework

Montgomery County Community College
General Chemistry - Inorganic
CHE 121
Worksheet #1
Worksheet Chapter 1. Matter and Measurements Part I
Name__Jeongmin Yi____
1. Classify the following as being a physical or a chemical change. Explain your
rational for your classification.
a. burning a candle (Hint: Is burning the same as melting?)
Chemical, combustion of products melts the wax and releases carbon
b. stirring cake batter
Physical, no formation of new substance, just mixing
c. dissolving sugar in water
Physical, just creation of aqueous solution, no new substance created
d. decomposition of limestone by heat
Physical, just changing the state of the rock into lava
e. a leaf turning yellow
Chemical, occurs due to chemical breakdown of chlorophyll in the leaf
f. formation of bubbles in a pot of water long before the water boils
Physical, we don’t know enough otherwise?
2. Classify each material as an element, compound, or mixture:
a. Paint
Mixture
b. Sodium chloride (table salt)
Compound
c. Copper
Element
d. Wine
Mixture
3. Give the symbols for each of the following elements:
a.
b.
c.
d.
e.
Silver
Hydrogen
Manganese
Magnesium
Potassium
Ag
H
Mn
Mg
K
4. Give the names for each of these elements:
a. Sn
Tin
b. Ni
Nickel
c. Zn
Zinc
d. Ne
Neon
e. He
Helium
f. Ca
Calcium
g. Cl
Chlorine
5. Write formulas for the following compounds; the atomic composition is given.
a. Hydrogen chloride: 1 atom hydrogen + 1 atom chlorine
HCl
b. Methane: 1 atom carbon + 4 atoms hydrogen
CH4
c. Glucose: 6 atoms carbon + 12 atoms hydrogen + 6 atoms oxygen
C6H1206
6. How many atoms of each element are represented in each formula?
a. H2 2 atoms of Hydrogen
b. Ba(C2H3O2)2 1 Barium + 4 Carbon + 6 Hydrogen + 4 Oxygen
c. HC2H3O2
4 Hydrogen + 2 Carbon + 2 Oxygen
7. Investigate the importance of iron in the body. Briefly describe how iron is used
in the body and what occurs when the iron levels in the body are too high or too
low. What can be medically done to help a patient with excess levels of iron?
(Use a reliable source. An internet source is fine.)
Most of the body’s iron is found in hemoglobin. The function of iron
is to transport oxygen throughout the body through the red blood
cells. When iron levels are low, the carrying capacity of oxygen in
the red blood cells are low. When there are excessive levels of iron,
hemochromatosis and an excess of red blood cells can occur in the
body. Medically, patients can take iron chelators to remove excess
iron from the body via urine or feces.
Montgomery County Community College
General Chemistry - Inorganic
CHE 121
Worksheet #2
Worksheet Chapter 1. Matter and Measurement Part II
Name____________
1. How many significant figures are in each of these numbers?
a. 3.025 ft. 4 sig figs
b. 0.001 mi. 1 sig fig
c. 12.20 L
4 sig figs
2. Write the following values in scientific notation:
9
a. 4,500,000,000 (2 significant figures) 4.5 * 10
b. 0.000123
1.23 * 10-4
3. Carry out the following calculations and express each answer to the correct
number of significant figures and appropriate units:
a. 213 mi./4.2 hr. =
51 mph
b. 119.1 in. – 3.44 in. = 116 in
c. (8.2 g + 0.125 g)/4.07 mL = 2.0 g/mL
4. How many cubic centimeters (cm 3) are in a box that measures 2.20 in. by 4.00 in.
by 6.00 in.?
2.20in*2.54cm/in=5.588cm
4.00in*2.54cm/in=10.16cm
6.00in*2.54cm/in=15.24cm
865 cm3
OR
(2.54cm)3/(1in)3=16.387064 cm3/in3
(2.2*4*6) = 52.8in3 *(16.387064 cm3/in3)=
865cm3
5. What temperature on the Fahrenheit scale corresponds to -8.0 ºC?
(-8°C × 9/5) + 32 = 17.6°F
18°F
6. The density of gold is 19.3 g/mL. What is the mass of 25.0 mL of gold?
19.3 g/mL * 25.0 mL = 482.5 g
483 grams
7. How many grams of gold are there in a pure sample with a volume of 1.5L?
(density Au = 19.3 g/ml)
1.5 L = 1500 mL
19.3 g/mL * 1500 mL = 28950 g
29000 grams
8. A sample of pure gold with a volume of 75.0 mL has a measured mass of 1448 g.
What is the density of the gold sample?
1448g/75.0mL = 19.306666
19.3 g/mL
9. Calculate the specific heat of a solid in J/gºC if 1638 J raises the temperature of
125 g of solid from 25.0 ºC to 52.6 ºC.
q = mcΔT
1638 J = 125g (c) * (52.6ºC-25.0ºC)
13.104 J/g = c*27.6ºC
C=0.4747826 J/gºC
C=0.475 J/gºC
Convert your specific heat value into units of cal/gºC