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3 years ago

Why must each atom of an element always have the same number of protons?

1 answer:

8 0

Atoms do not always contain the same number of electrons and protons, although this state is common. When an atom has an equal number of electrons and protons, it has an equal number of negative electric charges (the electrons) and positive electric charges (the protons). The total electric charge of the atom is therefore zero and the atom is said to be neutral. In contrast, when an atom loses or gains an electron (or the rarer case of losing or gaining a proton, which requires a nuclear reaction), the total charges add up to something other than zero.

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True or false when matter changes it’s state it is a physical change because it is the same substance the whole time.

Blababa [14]

Answer:

true

Explanation:

5 0

3 years ago

If calcium chloride is dissolved in water, what can be said about the concentration of the calcium ion? a. It has the same conce

e-lub [12.9K]

Answer:

b. Its concentration is half that of the chloride ion

Explanation:

As the calcium chloride formula is CaCl2

CaCl2 <--> Ca + 2 Cl-

4 0

3 years ago

Carl walked 12m north then turned around and walked back 4m south. What was his

aleksklad [387]

Answer:

Distance: 16m Displacement: 8m North

Explanation:

Total distance is the total amount traveled, regardless of direction. So, you would just add 12 and 4 to get a total distance of 16m. Displacement is the distance/direction from the start to the end point, regardless of which way you got there. So, to find displacement, you just subtract:

12m North - 4m South = 8m North

** I could be wrong so definitely double check this answer with a similar question**

3 0

3 years ago

0.10 M potassium chromate is slowly added to a solution containing 0.20 M AgNO3 and 0.20 M Ba(NO3)2. What is the Ag+ concentrati

erastova [34]

Answer:

$[Ag^{+}]=4.2\times 10^{-2}M$

Explanation:

Given:

[AgNO3] = 0.20 M

Ba(NO3)2 = 0.20 M

[K2CrO4] = 0.10 M

Ksp of Ag2CrO4 = 1.1 x 10^-12

Ksp of BaCrO4 = 1.1 x 10^-10

$BaCrO_4 (s)\leftrightharpoons Ba^{2+}(aq)\;+\;CrO_{4}^{2-}(aq)$

$Ksp=[Ba^{2+}][CrO_{4}^{2-}]$

$1.2\times 10^{-10}=(0.20)[CrO_{4}^{2-}]$

$[CrO_{4}^{2-}]=\frac{1.2\times 10^{-10}}{(0.20)}= 6.0\times 10^{-10}$

Now,

$Ag_{2}CrO_4(s) \leftrightharpoons 2Ag^{+}(aq)\;+\;CrO_{4}^{2-}(aq)$

$Ksp=[Ag^{+}]^{2}[CrO_{4}^{2-}]$

$1.1\times 10^{-12}=[Ag^{+}]^{2}](6.0\times 10^{-10})$

$[Ag^{+}]^{2}]=\frac{1.1\times 10^{-12}}{(6.0\times 10^{-10})}= 1.8\times 10^{-3}$

$[Ag^{+}]=\sqrt{1.8\times 10^{-3}}=4.2\times 10^{-2}M$

So, BaCrO4 will start precipitating when [Ag+] is 4.2 x 1.2^-2 M

7 0

3 years ago

Question 2(Multiple Choice Worth 3 points) What happens to the rate of most reactions as the reaction progresses? The rate remai

Sav [38]

Answer: -

The rate decreases as the concentration of the reactants decreases

Explanation: -

A reaction involves change of the reactants into products.

Initially there is only reactants. So the rate if reaction is high.

After some time there are products. So the amount of reactant is less.

Reactions involve collisions of reactant molecules. As the reactant amount decreases, collisions between the reactants decreases. As such the rate of reaction decreases with the progress of the reaction.

3 0

3 years ago