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3 years ago

List two things that do not change between isotopes of an element

Chemistry

2 answers:

sergij07 [2.7K]3 years ago

8 0

Answer:

Because different isotopes have different numbers of neutrons, they do not all weigh the same or have the same mass. Different isotopes of the same element have the same atomic number. They have the same number of protons. The atomic number is decided by the number of protons.

Lady bird [3.3K]3 years ago

5 0

Answer:

Explanation:

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how many mL of a 3.5 M sodium hydroxide will be needed to neutralize 15mL of a 4.3 M hydrochloric acid solution?

kobusy [5.1K]

Step 1 : write a valanced equation..
NaOH + HCl 》NaCl + H2O

Step 2 : find the number of mole of HCl..
1000 ml ..contains 4.3 mole
15ml... (4.3÷1000)×15 =...

Stem 3 : use mole ratio....
HCl : NaOH
1 : 1
So mole is same as calculated above...

Step 4 :
3.5 mole of NaOH is in 1000ml
(4.3÷1000)×15 mole is in ....

Do the calculation

6 0

3 years ago

For the reaction 2NOCl(g) <-----> 2NO(g) + Cl2(g), Kc = 8.0 at a certain temperature. What concentration of NOCl must be p

Nat2105 [25]

Answer is: concentration of NOCl is 3.52 M.

Balanced chemical reaction: 2NOCl(g) ⇄ 2NO(g) + Cl₂(g).
Kc = 8.0.
[NOCl] = 1.00 M; equilibrium concentration.
[NO] = x.
[Cl₂] = x/2; equilibrium concentration of chlorine.
Kc = [Cl₂] ·[NO]² / [NOCl].
8.00 = x/2 · x² / 1.
x³/2 = 8.
x = ∛16.
x = 2.52 M.
co(NOCl) = [NOCl] + x.
co(NOCl) = 1.00 M + 2.52 M.
co(NOCl) = 3.52 M; the initial concentration of NOCl.

7 0

2 years ago

Draw the product of the reaction CH3CH2CH2CH2C?CCH3+2Br2??

svetlana [45]

I will assume that the sign ? between the C and the CCH3 is a triple bond, and I will represent it by three vertical lines |||

So the reaction is:

CH3CH2CH2CH2C ||| CCH3+2Br2 ---->

This is a typical reaction known as halogenation of alkines.

This is an addition reaction, i.e. the alkyne undergoes an addition of the Br2 (and it also happens with Cl2) to the triple bond to form a tetra halide.

.
 Br Br
 | |
CH3CH2CH2CH2C ||| CCH3+2Br2 ----> CH3 CH2 CH2 CH2 C - C - CH3
 | |
 Br Br

3 0

3 years ago

A scientist digs up sample of arctic ice that is 458,000 years old. He takes it to his lab and finds that it contains 1.675 gram

Fiesta28 [93]

Answer:

6.70 grams of krypton-81 was present when the ice first formed

Explanation:

Let use the below formula to find the amount of sample

$N= N_0(\frac{1}{2})^n$

where

$n = \frac{t}{t_{\frac{1}{2}}}$

here

t = 458,000 years

$t_{\frac{1}{2}}$ = 229,000

$\frac{t}{t_{\frac{1}{2}}}$ = \ $\frac{ 458,000}{229,000}$

n = $\frac{t}{t_{\frac{1}{2}}}$ = 2.000

Now substituting the values

$1.675 = N_0(\frac{1}{2})^{2.000}}$

$1.675 = N_0\times (0.2500)$

$N_0= \frac{1.675}{0.2500}$

$N_0=6.70$

3 0

3 years ago

Which phrase is the best description of a topographic map? A shows the physical features of the land B shows political boundarie

Black_prince [1.1K]

A shows the physical features of the land

Explanation:

A topographic map is a map that shows the physical features of the land area. Rivers, streams, mountains, valleys, hills and other physical features.

A topographic map is made up of series of contour lines.
The contour lines are lines that joins places of equal elevation.
All places on the contour lines have the same elevation.
Using the contour lines, we can understand the landforms in an area.
Other map keys are used to delineate settlement patterns, streams, churches, dams and the like.
Most topographic maps are used as base maps for making other maps.

learn more:

Physical map brainly.com/question/3687554

#learnwithBrainly

8 0

3 years ago

Read 2 more answers