The ability of a substance to undergo specific chemical changes *

How many moles are in 1.806 x 1024 molecules of bromine?

Pepsi [2]

<h3>Answer:</h3>

2.999 mol Br

<h3>General Formulas and Concepts:</h3>

Math

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Chemistry

Atomic Structure

Using Dimensional Analysis
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

<h3>Explanation:</h3>

Step 1: Define

1.806 × 10²⁴ molecules Br

Step 2: Identify Conversions

Avogadro's Number

Step 3: Convert

$\displaystyle 1.806 \cdot 10^{24} \ molecules \ Br(\frac{1 \ mol \ Br}{6.022 \cdot 10^{23} \ molecules \ Br} )$ = 2.999 mol Br

Step 4: Check

We are given 4 sig figs. Follow sig fig rules and round.

Our final answer is already in 4 sig figs, so there is no need to round.

7 0

3 years ago

Read 2 more answers

A 1250.0g block of silver at 1oC is placed in 2.6g of water vapor at 102oC. What is the equilibrium temperature of the two subst

skad [1K]

Answer:

Explanation:

Let final temperature be T .

vapor is at 102⁰C

loss of heat by vapor in turning into water at 100⁰C

= 2.6 x 2 x 1.996 + 2.6 x 2260 = 5886.37 J

loss of heat to lower temperature to T

2.6 x 4.186 x ( 100 - T )

1088.36 - 10.88 T

Total heat loss = 5886.37 + 1088.36 - 10.88 T

= 6974.73 - 10.88 T

heat gain by silver to gain temperature from 1⁰C to T⁰C

= 1250 x ( T - 1 ) x .235 = 293.75 T - 293.75

heat gain = heat loss

293.75 T - 293.75 = 6974.73 - 10.88 T

304.63 T = 7268.48

T = 23.86°C .

6 0

4 years ago

(1.) Using Beer's Law, How will the absorbance measured for the solutions change as the concentration of aspirin in solutions in

Vesnalui [34]

Answer:

(1) The absorbance of the aspirin in solutions will increase.

(2) [ASA]f = 3.79x10⁻⁴M

(3) [ASA]i = 3.79x10⁻³M

(4) m ASA = 0.171g

Explanation:

The Beer's Law is expressed by:

$A = \epsilon \cdot l \cdot C$ (1)

where A: is the absorbance of the species, ε: is the molar attenuation coefficient, l: is the pathlength and C: is the concentration of the species

(1) From equation (1), the relation between the absorbance of the species and its concentration is directly proportional, so if the aspirin concentration in solutions increases, the absorbance of the solutions will also increase.

(2) Starting in the given expression for the relationship between absorbance and concentration of ASA, we can calculate its concentration in the solution:

$A = 1061.5 \cdot [ASA]$

$[ASA] = \frac{A}{1061.5} = 3.79 \cdot 10^{-4}M$

Therefore, the aspirin concentration in the solution is 3.79x10⁻⁴ M

(3) To calculate the stock solution concentration, we can use the next equation:

$V_{i} [ASA]_{i} = V_{f} [ASA]_{f}$

where Vi: is the stock solution volume=10mL, Vf: is the solution diluted volume=100mL, [ASA]i: is the aspirin concentration of the stock solution and [ASA]f: is the aspirin concentration of the diluted solution

$[ASA]_{i} = \frac{V_{f} \cdot [ASA]_{f}}{V_{i}} = \frac {100mL \cdot 3.79\cdot 10^{-4} M}{10mL} = 3.79 \cdot 10^{-3} M$

Hence, the concentration of the stock solution is 3.79x10⁻³M

(4) To determine the aspirin mass in the tablet, we need to use the following equation:

$m_{ASA} = \eta_{ASA} \cdot M_{ASA} = [ASA]_{i} \cdot V_{0} \cdot M_{ASA}$

where η: is the aspirin moles = [ASA]i V₀, M: is the molar mass of aspirin=180.158g/mol, V₀: is the volume of the volumetric flask=250mL and [ASA]i: is the aspirin concentration in the volumetric flask which is equal to the stock solution=3.79x10⁻³M

$m_{ASA} = 3.79 \cdot 10^{-3} \frac{mol}{L} \cdot 0.250L \cdot 180.158 \frac{g}{mol} = 0.171 g$

Then, the aspirin mass in the tablet is 0.171 g.

I hope it helps you!

5 0

3 years ago

Absorption of a light wave causes atoms and molecules to vibrate. These vibrations create ________ energy.

dedylja [7]

To create kenetic energy

4 0

3 years ago

How can I identify a salt compound is acidic,basic,neutral

Luden [163]

Salts that are from strong bases and strong acids do not hydrolyze. Salts that are from strong bases and weak acids do hydrolyze, which gives it a pH greater than 7. Salts of weak bases and strong acids do hydrolyze, which gives it a pH less than 7.

7 0

3 years ago