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3 years ago

How do calculate the mass number of an atom

2 answers:

4 0

To calculate the atomic mass of a single atom of an element, add up the mass of protons and neutrons. Example: Find the atomic mass of an isotope of carbon that has 7 neutrons. You can see from the periodic table that carbon has an atomic number of 6, which is its number of protons.

Verizon [17]3 years ago

3 0

You add the protons and the nuetrons together i think

You might be interested in

How many grams of na2co3 would be needed to produce 1000g of nahco3

Ivenika [448]

Answer:

630.95 grams of Na₂CO₃ would be needed to produce 1000g of NaHCO₃

Explanation:

The balanced reaction is:

Na₂CO₃ + CO₂+ H₂O → 2 NaHCO₃

By stoichiometry of the reaction (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of each compound participate in the reaction:

Na₂CO₃: 1 moles
CO₂: 1 mole
H₂O: 1 mole
NaHCO₃: 2 moles

Being the molar mass:

Na₂CO₃: 106 g/mole
CO₂: 44 g/mole
H₂O: 18 g/mole
NaHCO₃: 84 g/mole

Then by stoichiometry the following quantities of mass participate in the reaction:

Na₂CO₃: 1 mole* 106 g/mole= 106 g
CO₂: 1 mole* 44 g/mole= 44 g
H₂O: 1 mole* 18 g/mole= 18 g
NaHCO₃: 2 moles* 84 g/mole= 168 g

You can apply the following rule of three: if 106 grams of Na₂CO₃ are needed to produce 168 grams of NaHCO₃, how much mass of Na₂CO₃ is necessary to produce 1000 grams of NaHCO₃?

$mass of Na_{2} CO_{3}=\frac{1000grams ofNaHCO_{3} *106gramsofNa_{2} CO_{3} }{168grams ofNaHCO_{3}}$

mass of Na₂CO₃= 630.95 grams

630.95 grams of Na₂CO₃ would be needed to produce 1000g of NaHCO₃

6 0

3 years ago

Calculate the hydronium ion concentration in an aqueous solution with a pH of 11.7 at 25°C.

DENIUS [597]

Answer:

Approximately $2\times 10^{-12}\;\rm mol \cdot L^{-1}$ .

Explanation:

The hydronium ion concentration $\left[\mathrm{H_3O^{+}}\right]$ of an aqueous solution can be found from its $\rm pH$ with the equation:

$\displaystyle \left[\mathrm{H_3O^{+}}\right] = 10^{-\mathrm{pH}}$ .

For this solution, $\rm pH= 11.7$ . Hence,

$\begin{aligned}& \left[\mathrm{H_3O^{+}}\right] \\ &= 10^{-\mathrm{pH}} \\ &= 10^{-11.7} \approx 2 \times 10^{-12}\end{aligned}$ .

Note that for this equation, the number of significant figures in $\left[\mathrm{H_3O^{+}}\right]$ should be the same as the number of decimal places in $\rm pH$ . For example, the $\rm pH$ of this question comes with only one decimal place. As a result, there would be only one significant figure in the $\left[\mathrm{H_3O^{+}}\right]$ obtained from the equation.

6 0

3 years ago

Provide IUPAC names od the following compound.

ch4aika [34]

Answer:

butanal

Explanation:

4 C= butane

pfg (aldehyde=al) lowest #

5 0

3 years ago

Using the table above, calculate the atomic mass of the unknown element.

sleet_krkn [62]

Hehehehejdjdjdjjdjdjjdjdjdjjfjdjr

6 0

3 years ago

If you were asked to convert 25 cg to the unit hg, which of the following would be the first fraction used in the conversion? on

zhannawk [14.2K]

We are asked to convert 25 cg to units of hg.

1 cg = 1 centigram = 10⁻² g
1 hg = 1 hectogram = 10² g

The options given are:

a) 1 hg/ 10² g
b) 10² cg/ 1 hg
c) 10² hg/ 1 cg
d) 10⁻² g/ 1 cg

To convert 25 cg to 1 hg, we could convert the 25 cg to grams first, then grams to hg.

25 cg · 10⁻² g/ 1cg = 0.25 g

Here we have converted our number from cg to grams. We can use another conversion of grams to hg to complete the conversion.

0.25 g · 1 hg/ 10² g = 0.0025 hg

Therefore, the first conversion we used was d) 10⁻² g/ 1 cg.

4 0

3 years ago