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2 years ago

If 2a=3b and a=6 then b=

Chemistry

2 answers:

Ne4ueva [31]2 years ago

6 0

then b is 4

2a=3b since a=6

2x6=3b

12=3b

b=12/3

b=4

Naya [18.7K]2 years ago

4 0

Answer:

b=4

Explanation:

2a=3b

2a=2*6

2*6=12

2a=12

12=3b

12/3=4

b=4

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Movement from place to palce

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2 years ago

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2. 27.8 mL of an unknown were added to a 50.0-mL flask that weighs 464.7 g. The total mass of the flask and the liquid is 552.4

agasfer [191]

Answer:

$d=4.24x10^{-4}\frac{lb}{in^3}$

Explanation:

Hello there!

In this case, according to the given information, it turns out firstly necessary for us to set the equation for the calculation of density and mass divided by volume:

$d=\frac{m}{V}$

Thus, we can find the mass of the unknown by subtracting the total mass of the liquid to the mass of the flask and the liquid:

$m=552.4g-464.7g=87.7g$

So that we are now able to calculate the density in g/mL first:

$d=\frac{87.7g}{27.8mL}=3.15g/mL$

Now, we proceed to the conversion to lb/in³ by using the following setup:

$d=3.15\frac{g}{mL}*\frac{1lb}{453.6g}*\frac{1in^3}{16.3871mL}\\\\d=4.24x10^{-4}\frac{lb}{in^3}$

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6 0

2 years ago

Aspirin (acetylsalicylic acid, C9H8O4) is a weak monoprotic acid. To determine its acid-dissociation constant, a student dissolv

Triss [41]

Answer:

1. $3.57\times 10^{-4}$ was the $K_a$ value calculated by the student.

2. $5.93\times 10^{-4}$ was the $K_b$ of ethylamine value calculated by the student.

Explanation:

The $pH$ value of Aspirin solution = 2.62

$pH=-\log[H^+]$

$[H^+]=10^{-2.62}=0.00240 M$

Moles of s asprin = $\frac{2.00 g}{180 g/mol}=0.01111 mol$

Volume of the solution = 0.600 L

The initial concentration of Aspirin = c = $\frac{0.01111 mol}{0.600 L}=0.0185 M$

$HAs\rightleftharpoons As^-+H^+$

initially

c 0 0

At equilibrium

(c-x) x x

The expression of dissociation constant :

$K_a=\frac{[As^-][H^+]}{[HAs]}$ :

$K_a=\frac{x\times x }{(c-x)}$

$=\frac{0.00240 M\times 0.00240 M}{(0.0185-0.00240 )}$

$K_a=3.57\times 10^{-4}$

$3.57\times 10^{-4}$ was the $K_a$ value calculated by the student.

The $pH$ value of ethylamine = 11.87

$pH+pOH=14$

$pOH=14-11.87=2.13$

$pOH=-\log[OH^-]$

$[OH^-]=10^{-2.13}=0.00741 M$

The initial concentration of ethylamine = c = 0.100 M

$C_2H_5NH_2+H_2O\rightleftharpoons C_2H_5NH_3^{+}+OH^-$

initially

c 0 0

At equilibrium

(c-x) x x

The expression of dissociation constant :

$K_b=\frac{[C_2H_5NH_3^{+}][OH^-]}{[C_2H_5NH_2]}$ :

$K_b=\frac{x\times x}{(c-x)}$

$=\frac{0.00741\times 0.00741}{(0.100-0.00741)}$

$K_b=5.93\times 10^{-4}$

$5.93\times 10^{-4}$ was the $K_b$ of ethylamine value calculated by the student.

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2 years ago

Define significant figure. Discuss the importance of using the proper number of significant figures in measurements and calculat

anastassius [24]

Explanation:

Significant figure is the measure of how accurately something can be measured. It carries meaning contributing to its measurement resolution. It is important to use proper number of significant figures to get a precise measurement. For example, if we use a meter stick then measurements like 0.874 meters, or 0.900 meters, are good because they indicate that we can measure to the nearest millimeter. Whereas a measurement like 0.8 does not tell that a meter stick can measure to the nearest millimeter.

7 0

2 years ago

A chemist burns 0.8 g of iron in oxygen.

stich3 [128]

Answer:

0.3g

Explanation:

1.1 - 0.8 = 0.3

Hope this helps

7 0

2 years ago