The half life or radium 226 is 1630 years

A lead mass is heated and placed in a foam cup caloriemeter containing 40.0mL of water at 17.0 C. The water reaches a temperatur

Mrrafil [7]

the Answer is 502 Joules

8 0

3 years ago

What is the molarity of a sodium chloride solution made by dissolving 4.512 moles to make 2.0 L?

Svet_ta [14]

Answer:

2.40 M

Explanation:

The molarity of a solution tells you how many moles of solute you get per liter of solution.

Notice that the problem provides you with the volume of the solution expressed in milliliters,

mL

. Right from the start, you should remember that you must convert this volume to liters by using the conversion factor

1 L

=

10

3

mL

Now, in order to get the number of moles of solute, you must use its molar mass. Now, molar masses are listed in grams per mol,

g mol

−

1

, which means that you're going to have to convert the mass of the sample from milligrams to grams

1 g

=

10

3

mg

Sodium chloride,

NaCl

, has a molar mass of

58.44 g mol

−

1

, which means that your sample will contain

unit conversion



280.0

mg

⋅

1

g

10

3

mg

⋅

molar mass



1 mole NaCl

58.44

g

=

0.004791 moles NaCl

This means that the molarity of the solution will be

c

=

n

solute

V

solution

c

=

0.004791 moles

2.00

⋅

10

−

3

L

=

2.40 M

The answer is rounded to three sig figs, the number of sig figs you have for the volume of the solution.

6 0

3 years ago

A gas has a volume of 590 mL at temperature of -55.0 C. What volume will the gas occupy at 30.0 C show your work

DENIUS [597]

Data:
$V_{initial} = 590\:mL$
$T_{initial} = -55.0^0C$
converting to Kelvin
TK = TC + 273
TK = -55.0 + 273 → TK = 218.0 → $T_{initial} = 218.0\:K$
$V_{final} = ? (in\:milliliters)$
$T_{final} = 30.0^0C$
TK = TC + 273
TK = 30.0 + 273 → TK = 303.0 → $T_{final} = 303.0\:K$

By the first Law of Charles and Gay-Lussac, we have:
$\frac{ V_{i} }{ T_{i} } = \frac{ V_{f} }{ T_{f} }$

Solving:
$\frac{ V_{i} }{ T_{i} } = \frac{ V_{f} }{ T_{f} }$
$\frac{ 590 }{ 218.0 } = \frac{ V_{f} }{ 303.0 }$
Product of extremes equals product of means:
$218.0* V_{f} = 590*303.0$
$218.0 V_{f} = 178770$
$V_{f} = \frac{178770}{218.0}$
$\boxed{\boxed{V_{f} \approx 820.04\:mL}}\end{array}}\qquad\quad\checkmark$

7 0

3 years ago

You are performing an experiment that uses 114Ag. 113Ag is radioactive, decays by beta-- emission and has a half-life of 21 minu

maxonik [38]

Answer: The 234.74 grams of sample should be ordered.

Explanation:

Let the gram of 114 Ag to ordered be $N_o$