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3 years ago

I'm kinda in a rush but take your time!Thx! 1.What was Henri Becquerel studying when he accidentally discovered radioactivity?

Chemistry

1 answer:

zzz [600]3 years ago

4 0

1.C
2.B
3.B
4.D
Are the answers I got

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Which of the following is the greatest mass? Select one:

algol13

Answer:

B. 1.000 × 10-4 kg

Explanation:

A. 1.000 × 10-8 Mg = 0.00000001 Mg = 0.1 mg

B. 0.0001 kg = 0.1 g

C. 1000 ug = 1 mg

D. 1 .000 × 10-2 cg = 0.01 cg = 0.1 mg

A = D

B > C > A = D

8 0

3 years ago

The atomic mass of an element is the weighted average of the(1) number of protons in the isotopes of that element(2) number of n

liberstina [14]

It is a weighted average of the atomic masses of the naturally occurring isotopes of the element.

4 0

3 years ago

The pH of a 0.78M solution of 4-pyridinecarboxylic acid HC6H4NO2is measured to be 2.53.Calculate the acid dissociation constant

nika2105 [10]

Answer : The value of acid dissociation constant is, $1.1\times 10^{-5}$

Solution : Given,

Concentration pyridinecarboxylic acid = 0.78 M

pH = 2.53

First we have to calculate the hydrogen ion concentration.

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

$2.53=-\log [H^+]$

$[H^+]=2.95\times 106{-3}M$

Now we have to calculate the acid dissociation constant.

The equilibrium reaction for dissociation of (weak acid) is,

$HC_6H_4NO_2\rightleftharpoons C_6H_4NO_2^-+H^+$

initially conc. 0.78 0 0

At eqm. (0.78-x) x x

The expression of acid dissociation constant for acid is:

$k_a=\frac{[C_6H_4NO_2^-][H^+]}{[C_6H_4NO_2]}$

As, $[H^+]=[C_6H_4NO_2^-]=x$

So, $x=2.95\times 106{-3}M$

Now put all the given values in this formula ,we get:

$k_a=\frac{(x)\times (x)}{(0.78-x)}$

$k_a=\frac{(2.95\times 106{-3})\times (2.95\times 106{-3})}{(0.78-2.95\times 106{-3})}$

$K_a=1.1\times 10^{-5}$

Therefore, the value of acid dissociation constant is, $1.1\times 10^{-5}$

7 0

4 years ago

In a chemical equation, the symbol that takes the place of the word yields is an) Example: HCI + KOH-KCI + H2O

Masteriza [31]

Answer:

Arrow.

Explanation:

Hello!

In this case, since chemical reactions are characterized by the presence of some species at the left on an arrow representing the reactants and at the right the products, we understand that the arrow, separating reactants and products is understood as "produces" or in very chemical words "yields"; therefore, the symbol that takes the place of the word yields is an arrow.

Best regards!

4 0

3 years ago

1(a). What is the solubility of calcium chloride (CaCl2) at 5°C?

In-s [12.5K]

Answer:

60 g/100 g water

Explanation:

Find 5 °C on the horizontal axis.

Draw a line vertically from that point until you reach the solubility curve for CaCl₂.

Then draw a horizontal line from there to the vertical axis.

The solubility of CaCl₂ is 60 g/100 g water.

7 0

3 years ago