Chemistry Test

what is the specific heat of an unknown substance if 100.0g of it at 200.0 C reaches an equilibrium temperature of 27.1 C when it comes in contact with a calorimeter of water. the water weighs 75g and had an initial temperature of 20.00 C

0.129 J/gC

what is the molarity of a solution made by diluting 26.5 mL of 6.00 M HNO3 to a volume of 250 mL?

0.636 M

which sample has the lowest entropy?

1 mole of KNO3(s)

how many moles of NaCl are present in a solution with a molarity of 8.59 M and 125 mL of solution?

1.07 mol

how many moles of NaCl are present in a solution with a molarity of 8.59 M and a volume of 125 mL?

1.07 mol

the temperature of an unknown piece of metal with a mass of 30.00g changes from 25.0 C to 35.0 C when the metal absorbs 350.0 J of energy. what is the specific heat of the metal?

1.17 J/gC

calculate the molarity of the following solution : 1.0 mole of KCl in 750.0 mL of solution

1.3 M

there are 2 pans of water, one has 100 mL in it and one has 1000 mL. you add 4000 Joules of energy, which one has the bigger change in temperature?

100 mL

what volume of 1.50 M KBr can be made from 15.6 mL of concentrated KBr with a molarity of 9.65 M?

100 mL

the specific heat (C) of copper is 0.39 J/gC. what is the temperature change (△t) when 100 Joules of heat (Q) is added to 20 grams?

12.82 C

calorimetry question : a piece of metal with a mass of 32.8 g is heated to 100.5 C and dropped into 138.2 g of water at 20.0 C. the final temperature of the system is 30.2 C. what is the specific heat capacity of the metal?

2.56 J/gC

a sample of iron receives 50 J of heat energy that raises the temperature of the iron by 25 C. if iron has a specific heat of 0.10 J/gC, what is the mass of the iron sample?

20g

how many mL of 10.8 M HCL are required to make 100.0 mL of 3.00 M acid?

27.8 mL

which sweet tea would you expect to taste the sweetest?

3.1 M

20 g of water, specific heat of water is 4.18 J/gC. temperature changes from 25 C to 20 C, how much heat energy (Q) moves from the water to the surroundings?

418 J

the specific heat of water is 4.18 J/gC. if 980 J of energy is added to 6.20 g of water at 18.0 C, what is the final temperature of the water?

55.8 C

the specific heat of platinum is 0.133 J/gC. how much heat (Q) is released when a 10g piece of platinum cools from 100 C to 50 C?

66.5 J

a pot of 2400g of water at a temperature of 25 C is heated on a stove until the water boils (100 C). the specific heat of the water is 4.18 J/gC. determine the heat energy needed to heat the water in the pot to boiling

752,400 J

how many moles are needed to make 2.5 L of a 3.8 M solution?

9.5 mol

to find the pH of a solution you take the _______ of the H3O+ concentration

-log

what is the H+ concentration of a solution with a pH of 2?

.01 moles/L

if i have 340 mL of a 0.5 M NaBr solution, what will the concentration be if i add 560 mL more water to it?

.188 M

what is the molarity of 4g of NaCl (MM = 58.45) in 3,800 mL of solution?

0.018 M

if I dilute 250 mL of 0.20 M lithium acetate solution to a volume of 750 mL, what will the concentration of the final solution be?

0.03 M

hydrochloric acid (HCl) and acetic acid (HC2H3O2) are both acids. HCl completely dissociates in water, while HC2H3O2 does not. which of the following statements best describes these two acids?

HCl is a strong acid, HC2H3O2 is a weak acid

what is the formula to calculate heat energy required to raise the temperature of any substance?

Q = mc△t

identify whether the following results in an increase or decrease in entropy : vaporization

increase

entropy increases from the solid, liquid, to gas. why?

molecular disorder increases

molarity is measured in ?

moles per L

if two objects have different temperatures when they come in contact, heat will flow from the warmer object to the cooler one UNTIL _________?

they both have an equal temperature

what would be the effect on the particles if more heat is supplied to the system?

they would speed up

T/F ? entropy is the measure of the number of possible ways that the energy of a system can be distributed

true

the table below shows the pH of several solutions. which solution has the greatest concentration of H+ ions?

vinegar

the SI unit of heat and energy is the ?

Joule

a compound that donates H+ ions is ?

a bronsted - lowry acid

what does "Q" mean?

a change in heat

which one of these would result in a decrease in entropy?

a liquid freezes

the entropy will usually increase when

all of these ( - a molecule is broken into two or more similar molecules - a reaction occurs that results in an increase in the number of moles to gas - a solid changes to liquid )

ammonium nitrate dissolves in water. it is a spontaneous endothermic process because the system undergoes ?

an increase in entropy

identify whether the following result is an increase or decrease in entropy gas --> liquid --> solid

decrease

which phase change represents a decrease in entropy?

gas to liquid

high randomness indicates ?

high entropy