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3 years ago

An atom has an atomic number of 12 and a mass number of 25. How many neutrons does the atom have?

1 answer:

6 0

Simple. The atomic number is the number of protons (12) and the mass number is the number of neutrons and protons combined. So you'd subtract 12 from 25 (25-12=) and that'd get you 13 as your answer. If you need to find the number of electrons, it'll be the same as the number of protons unless it has a certain charge and if it does, if it's positive it has more protons (+) than electrons (-), if it is negative it has more electrons (- negatively charged) than protons (+ positively charged)

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Which of the following might constitute an act of plagiarism?

Elina [12.6K]

Taking credit for a someone else's research or written work

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3 years ago

Read 2 more answers

Where does condensation occur?

shtirl [24]

The answer is B atmosphere (clouds )

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3 years ago

B. if 6.73 g of na2co3 is dissolved in enough water to make 250. ml of solution, what is the molar concentration of sodium carbo

BARSIC [14]

Answer:- $[Na_2CO_3]=0.254M$ , $[Na^+]=0.508 M$ , $[CO_3^2^-]=0.254M$

Solution:- We are asked to calculate the molarity of sodium carbonate solution as well as the sodium and carbonate ions.

Molarity is moles of solute per liter of solution. We have been given with 6.73 grams of sodium carbonate and the volume of solution is 250.mL. Grams are converted to moles and mL are converted to L and finally the moles are divided by liters to get the molarity of sodium carbonate.

Molar mass of sodium carbonate is 105.99 gram per mol. The calculations for the molarity of sodium carbonate are shown below:

$\frac{6.73gNa_2CO_3}{250.mL}(\frac{1mol}{105.99g})(\frac{1000mL}{1L})$

= $0.254MNa_2CO_3$

So, molarity of sodium carbonate solution is 0.254 M.

sodium carbonate dissociate to give the ions as:

$Na_2CO_3(aq)\rightarrow 2Na^+(aq)+CO_3^2^-$

There is 1:2 mol ratio between sodium carbonate and sodium ion. So, the molarity of sodium ion will be two times of sodium carbonate molarity.

$[Na^+]=2(0.254M)$ = 0.508 M

There is 1:1 mol ratio between sodium carbonate and carbonate ion. So, the molarity of carbonate ion will be equal to the molarity of sodium carbonate.

$[CO_3^2^-]=0.254M$

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4 years ago

The temperature of a system rises by 45°C during a heating process. Express this rise in temperature in Kelvin. (Round the final

postnew [5]

Answer:

45K

Explanation:

Rise in temperature = Final - initial temperature.

temperature in K = Temperature in Celsius + 273

for Celsius; T2 -T1 =45°C

for kelvin; T2+273 -(T1+273) = ?

T2+273 -T1-273 =?

T2-T1 = ?

T2-T1 =45k

hence ΔT(K) = ΔT(°C) (temperature difference in Celsius is equal to temperature difference in kelvin)

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3 years ago

Balance the following chemical equations.

solong [7]

Answer:

1) 2,1,2

2) 2,2,1,1

3)2,1,2

4)2,2,3

5)2,3,1,3

6 [ I cannot answer that]

7)6,1,2

3 0

4 years ago