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2 years ago

If Z is the symbol for an element, which pair among the following represents isotopes of the same element?

Chemistry

2 answers:

insens350 [35]2 years ago

5 0

the answer is B. got this correct on the test

anygoal [31]2 years ago

3 0

B. 51 50
Z and Z
25 25

It is because only this element have equal number of Protons (Bottom number) and are different in atomic masses (upper number)

Hope this helps!

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Ionic compounds involve a (share, tranfer) of electrons and typically involve atoms that have (Large, similar, very different) e

Juliette [100K]

Answer:

2 Transfer; very different

Explanation:

Ionic compound are compound that are formed from transfer of electron. The cations donate the electron(s) while the anion receive the electron(s). The compound possess a positively charged end and a negatively charge end. Example of ionic compound is NaCl . The sodium donates one electron to the chlorine to fulfill the octet rule. The sodium atom becomes positively charged as it donate electron to the chlorine atom. The chlorine atom becomes negatively charged as it receive electron from Sodium atom.

The atoms that are involve in forming ionic compound have very different electronegativity . Electronegativity is the measure of the ability of an atom to attract a bond pair of electron. For example the NaCl compound, the two atom has verse differences in the electronegativity. Cl atom is far more electronegative than Sodium atom.

6 0

2 years ago

Ionic bond form when one or more _ is transferred

Neko [114]

Answer:

Ionic bonds form between two or more atoms by the transfer of 1 or more electrons between atoms. Electron transfer produces negative ions called anions and positive ions called cations. ... In forming an chemical bond, the sodium atom, which is electropositive, loses its negatron to chlorine.

Explanation:

3 0

2 years ago

When nitrogen dioxide (NO2) from car exhaust combines with water in the air, it forms nitric acid (HNO3), which causes acid rain

yKpoI14uk [10]

Answer:

For a: The number of molecules of nitrogen dioxide is $4.52\times 10^{23}$

For b: The mass of nitric acid formed is 54.81 grams

For c: The mass of nitric acid formed is 206 grams

Explanation:

The given chemical reaction follows:

$3NO_2(g)+H_2O(l)\rightarrow 2HNO_3(aq.)+NO(g)$

For a:

By Stoichiometry of the reaction:

1 mole of water reacts with 3 moles of nitrogen dioxide

So, 0.250 moles of water will react with $\frac{3}{1}\times 0.250=0.75mol$ of nitrogen dioxide

According to mole concept:

1 mole of a compound contains $6.022\times 10^{23}$ number of molecules.

So, 0.75 moles of nitrogen dioxide will contain $0.75\times 6.022\times 10^{23}=4.52\times 10^{23}$ number of molecules

Hence, the number of molecules of nitrogen dioxide is $4.52\times 10^{23}$

For b:

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$ .....(1)

Given mass of nitrogen dioxide = 60.0 g

Molar mass of nitrogen dioxide = 46 g/mol

Putting values in equation 1, we get:

$\text{Moles of nitrogen dioxide}=\frac{60.0g}{46g/mol}=1.304mol$

By Stoichiometry of the reaction:

3 moles of nitrogen dioxide produces 2 mole of nitric acid

So, 1.304 moles of nitrogen dioxide will produce = $\frac{2}{3}\times 1.304=0.870$ moles of nitric acid

Now, calculating the mass of nitric acid from equation 1, we get:

Molar mass of nitric acid = 63 g/mol

Moles of nitric acid = 0.870 moles

Putting values in equation 1, we get:

$0.870mol=\frac{\text{Mass of nitric acid}}{63g/mol}\\\\\text{Mass of nitric acid}=(0.870mol\times 63g/mol)=54.81g$

Hence, the mass of nitric acid formed is 54.81 grams

For c:

For nitrogen dioxide:

Given mass of nitrogen dioxide = 225 g

Molar mass of nitrogen dioxide = 46 g/mol

Putting values in equation 1, we get:

$\text{Moles of nitrogen dioxide}=\frac{225g}{46g/mol}=4.90mol$

For water:

Given mass of water = 55.2 g

Molar mass of water = 18 g/mol

Putting values in equation 1, we get:

$\text{Moles of water}=\frac{55.2g}{18g/mol}=3.06mol$

By Stoichiometry of the reaction:

3 moles of nitrogen dioxide reacts with 1 mole of water

So, 4.90 moles of nitrogen dioxide will react with = $\frac{1}{3}\times 4.90=1.63mol$ of water

As, given amount of water is more than the required amount. So, it is considered as an excess reagent.

Thus, nitrogen dioxide is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

3 mole of nitrogen dioxide produces 2 moles of nitric acid

So, 4.90 moles of nitrogen dioxide will produce $\frac{2}{3}\times 4.90=3.27mol$ of nitric acid

Now, calculating the mass of nitric acid from equation 1, we get:

Molar mass of nitric acid = 63 g/mol

Moles of nitric acid = 3.27 moles

Putting values in equation 1, we get:

$3.27mol=\frac{\text{Mass of nitric acid}}{63g/mol}\\\\\text{Mass of nitric acid}=(3.27mol\times 63g/mol)=206g$

Hence, the mass of nitric acid formed is 206 grams

7 0

2 years ago

at 55 years what mass remains of a 200.0 g sample of a radioactive isotope with a half life of 10.0 years

Harman [31]

Answer:

4.419 g

Explanation:

55 years is 5.5 half lives

200 g * (1/2)^5.5 = 4.419 g

3 0

8 months ago

The partial negative charge at one end of a water molecule is attracted to the partial positive

Neporo4naja [7]

Answer:

Hydrogen Bond

Explanation:

Hydrogen bond interactions are formed between the hydrogen atom bonded to most electronegative atoms (i.e. F, O and N) of one molecule and most electronegative atom (i.e. F, O and N) of another molecule.

In this interaction the hydrogen atom has partial positive charge and electronegative atom has partial negative charge.

6 0

1 year ago