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mojhsa [17]
3 years ago
13

What part of an original isotope’s number of atoms remains have two half-lives?

Chemistry
1 answer:
KIM [24]3 years ago
3 0
After two half-lives, one fourth of the original isotope’s atom remain.
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How many moles of Na2SO4 can be made with 7.28 mol of H2SO4?
Slav-nsk [51]

Answer:

7.28 mol Na2SO4

Explanation:

Since it is already in moles, all we have to do is use a molar ratio

A molar ratio is the proportions of reactants and products using the balanced equation. When writing a mole ratio, the given information must cross out with the right thing.

7.28 mol H2SO4 * 1 mol Na2SO4/1 H2SO4 = 7.28 mol Na2SO4

*notice how the H2SO4 crosses out

5 0
2 years ago
Change these word equations into formula equations and balance them. Be sure to use the proper symbols to indicate the state of
Ket [755]

Answer:

See detailed reaction equations below

Explanation:

a) Mg(s) +2HBr(aq) ----------------> MgBr2(aq) + H2(g)

b) Ca(ClO3)2(s) ------------> CaCl2(s) + 3O2(g)

c) 3BaBr2(s) +2Na3PO4(aq) ------------> Ba3(PO4)2(s) + 6NaBr(aq)

d) 3AgNO3(aq) + AlI3(aq) --------------> 3AgI(s) + Al(NO3)3(aq)

Balancing reaction equations involves taking valencies and number of atoms of each element on the reactants and products side into consideration respectively.

3 0
3 years ago
Which of the following statements, if true, would support the claim that the NO3− ion, represented above, has three resonance st
tester [92]

Answer:

One of the bonds in nitrate is shorter than the other two.

Explanation:

We would firstly need to draw the Lewis structure for nitrate anion. To do this, let's follow the standard steps:

  • calculate the total number of valence electrons: five from nitrogen, each oxygen contributes 6, so a total of 18 from oxygen atoms, as well as one from the negative charge, we have a total of 24 valence electrons;
  • assign the central atom, usually this is the atom which is single; in this case, we have nitrogen as our central atom;
  • assign single bonds to all the terminal atoms (oxygen atoms);
  • assign octets to the terminal atoms and calculate the number of electrons assigned;
  • the number of electrons assigned is 24, so no lone pairs are present on nitrogen;
  • calculate the formal charges: each oxygen has a formal charge of -1 (formal charge is calculated subtracting the sum of lone pair electrons and bonds from the number of valence electrons of that atom); nitrogen has a formal charge of +2;
  • nitrogen doesn't have an octet as well, so we'll both minimize its formal charge and make it obtain an octet if we make one double bond N=O.

Therefore, we may have 3 resonance structures, as this double bond might be formed with any of the 3 oxygen atoms.

By definition, double bonds are shorter than single ones, so one of the bonds is shorter than the other two.

7 0
3 years ago
A bottle containing air is initially at a temperature of 33 degrees C and a pressure of 0.81 atm. After being placed in the free
Georgia [21]

Answer:

The final pressure is 0.725 atm.

Explanation:

Gay Lussac's Law establishes the relationship between pressure and temperature of a gas when the volume is constant. This law says that when there is a constant volume, as the temperature increases, the pressure of the gas increases. And when the temperature is decreased, the pressure of the gas decreases. That is, pressure and temperature are directly proportional quantities.

Mathematically, Gay-Lussac's law states that, when a gas undergoes a constant volume transformation, the quotient of the pressure exerted by the gas temperature remains constant:

\frac{P}{T}  =k

When analyzing an initial state 1 and a final state 2, the following is satisfied:

\frac{P1}{T1}  =\frac{P2}{T2}

In this case:

  • P1= 0.81 atm
  • T1= 33 C= 306 K
  • P2= ?
  • T2= 1 C= 274 K

Replacing:

\frac{0.81 atm}{306 K}  =\frac{P2}{274 K}

Solving:

P2=274 K*\frac{0.81 atm}{306 K}

P2= 0.725 atm

<u><em>The final pressure is 0.725 atm.</em></u>

4 0
2 years ago
Use the periodic table to determine which of the
ad-work [718]
A=79, N=44 lmk if I’m wrong ?
8 0
2 years ago
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