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3 years ago

What is the rule for determining the mass of an atom

Chemistry

1 answer:

Elena-2011 [213]3 years ago

5 0

Answer:

For any given isotope, the sum of the numbers of protons and neutrons in the nucleus is called the mass number. This is because each proton and each neutron weigh one atomic mass unit. By adding together the number of protons and neutrons and multiplying by 1, you can calculate the mass of the atom.

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If a 0.320 mM solution of MnO41- has an absorbance of 0.480 at 525 nm in a 1.000 cm cell. What is the concentration of a MnO41-

larisa [96]

Answer:

Hence the concentration of a MnO41- solution that has absorbance of 0.490 in the same cell at that wavelength is 0.3266.

Explanation:

Now A = el, el=const

Then,

$A2 / A1 = C2/ C1\\\\0.49/ 0.48 = C2 / 0.32\\\\C2 = 0.3266$

3 0

3 years ago

Which of the following (with specific heat capacity provided) would show the smallest temperature change upon gaining 200.0 J of

Brut [27]

Answer: The smallest temperature change is shown by water.

Explanation:

To calculate the heat absorbed or released, we use the equation:

$q=mC\times \Delta T$ ......(1)

where,

q = heat absorbed = 200.0 J

m = mass of the substance

C = specific heat of substance

$\Delta T$ = change in temperature

As, the same amount of heat is getting absorbed in all the cases. So, the change in temperature will depend on the product of mass and specific heat.

For the given options:

Option a: 50.0 g Fe, $C_{Fe}=0.449J/g^oC$

We are given:

$m=50.0g\\C_{Fe}=0.449J/g^oC$

Putting values in equation 1, we get:

$200.0J=50.0g\times 0.449J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{50\times 0.449}=8.99^oC$

Change in temperature = 8.99°C

Option b: 50.0 g water, $C_{water}=4.18J/g^oC$

We are given:

$m=50.0g\\C_{water}=4.18J/g^oC$

Putting values in equation 1, we get:

$200.0J=50.0g\times 4.18J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{50\times 4.18}=0.96^oC$

Change in temperature = 0.96°C

Option b: 25.0 g Pb, $C_{Pb}=0.128J/g^oC$

We are given:

$m=50.0g\\C_{Pb}=0.128J/g^oC$

Putting values in equation 1, we get:

$200.0J=25.0g\times 0.128J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{25\times 0.128}=62.5^oC$

Change in temperature = 62.5°C

Option d: 25.0 g Ag, $C_{Ag}=0.235J/g^oC$

We are given:

$m=25.0g\\C_{Ag}=0.235J/g^oC$

Putting values in equation 1, we get:

$200.0J=25.0g\times 0.235J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{25\times 0.235}=34.04^oC$

Change in temperature = 34.04°C

Option e: 25.0 g granite, $C_{granite}=0.79J/g^oC$

We are given:

$m=25.0g\\C_{Fe}=0.79J/g^oC$

Putting values in equation 1, we get:

$200.0J=25.0g\times 0.79J/g^oC\times \Delta T\\\\\Delta T=\frac{200}{25\times 0.79}=10.13^oC$

Change in temperature = 10.13°C

Hence, the smallest temperature change is shown by water.

5 0

3 years ago

What do acids and bases have in common apex?

disa [49]

Both acids and bases produce a part of a water molecule. Bases dissociate hydroxide (–OH) ions and acids, hydrogen (H+) ions that when combined form water. Both are also very corrosive when they are strong enough that they fully dissociate in water.

8 0

3 years ago

Read 2 more answers

Schach [20]

Answer:

2.74 M

Explanation:

Given data:

Mass of sodium chloride = 80.0 g

Volume of water = 500.0 mL

Molarity of solution = ?

Solution:

Molarity is used to describe the concentration of solution. It tells how many moles are dissolve in per litter of solution.

Formula:

Molarity = number of moles of solute / L of solution

Now we will convert the mL into L.

500.0 mL× 1 L /1000 mL = 0.5 L

In next step we will calculate the number of moles of sodium chloride.

Number of moles = mass/molar mass

Number of moles = 80.0 g/ 58.4 g/mol

Number of moles = 1.37 mol

Molarity:

M = 1.37 mol/ 0.5 L

M = 2.74 M

8 0

3 years ago

The following balanced equation shows the formation of water. 2H2 + O2 2H2O How many moles of oxygen (O2) are required to comple

motikmotik

Answer:

13.7 moles of O₂ are needed

Explanation:

In order to find the moles of reactants that may react to make the products we need to determine the reaction:

Reactants are hydrogen and oxygen

Product: Water

2 moles of hydrogen can react to 1 mol of oxygen and produce 2 moles of water.

Balanced reaction: 2H₂(g) + O₂(g) → 2H₂O(l)

If 2 moles of hydrogen need 1 mol of oxygen to react

Therefore, 27.4 moles of H₂ must need (27.4 .1) / 2 = 13.7 moles of O₂

8 0

3 years ago