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What type of energy is present in a barbell being lifted or a shot-put being thrown?

denpristay [2]

The type of energy used is kinetic energy. Kinetic energy is the energy of motion.

8 0

3 years ago

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What is the molarity of the solution formed by dissolving 80. G of NAOH(s) into water to give a total volume of 4.00 l

Mrrafil [7]

Answer:

0.5 M

Explanation:

From the question given above, the following data were obtained:

Mass of NaOH = 80 g

Volume of solution = 4 L

Molarity =?

Next, we shall determine the number of mole in 80 g of NaOH. This can be obtained as follow:

Mass of NaOH = 80 g

Molar mass of NaOH = 23 + 16 + 1

= 40 g/mol

Mole of NaOH =?

Mole = mass / molar mass

Mole of NaOH = 80 / 40

Mole of NaOH = 2 moles

Finally, we shall determine the molarity of the solution. This can be obtained as follow:

Mole of NaOH = 2 moles

Volume of solution = 4 L

Molarity =?

Molarity = mole / Volume

Molarity = 2/4

Molarity = 0.5 M

Therefore, the molarity of the solution is 0.5 M.

3 0

3 years ago

The pKa of lactic acid is 3.9. A lactate buffer will be useful from pH values ________. The pKa of lactic acid is 3.9. A lactate

Vedmedyk [2.9K]

Answer:

Explanation:

The usefulness of a buffer is its ability to resist changes in pH when small quantities of base or acid are added to it. This ability is the consequence of having both the conjugate base and the weak acid present in solution which will consume the added base or acid.

This capacity is lost if the ratio of the concentration of conjugate base to the concentration of weak acid differ by an order of magnitude. Since buffers having ratios differing by more will have their pH driven by either the weak acid or its conjugate base .

From the Henderson-Hasselbach equation we have that

pH = pKa + log [A⁻]/[HA]

thus

0.1 ≤ [A⁻]/[HA] ≤ 10

Therefore the log of this range is -1 to 1, and the pH will have a useful range of within +/- 1 the pKa of the buffer.

Now we are equipped to answer our question:

pH range = 3.9 +/- 1 = 2.9 through 4.9

7 0

3 years ago

What is chemisorption?

Blababa [14]

When the substance being absorbed is held together by chemical bonds.

6 0

3 years ago

This question in the screenshot

Morgarella [4.7K]

Mass of hydrate + crucible = 47.29 g

Mass of anhydrous salt = 2.7 g

Molar mass of anhydrous salt CuSO4 = 159.5 g

Given,

mass of empty crucible = 42.45 g

mass of hydrate salt= 4.84 g

mass of crucible after first heating = 46.1 g

mass of crucible after second heating= 45.153 g

mass of crucible after third heating= 45.15 g

so, as per the question we need to find...

Mass of hydrate + crucible = ? g

Mass of anhydrous salt = ? g

Molar mass of anhydrous salt CuSO4 = ? g

∴Mass of hydrate + crucible = 42.45 + 4.48 = 47.29 g

The given salt is in hydrate form, to remove water from this molecule we need to perform heating .

So we are taking the substance into the crucible as it is in less quantity.

Here, we performed heating 3 times and note the weight after every heating.

After this, assume that the water is totally evaporated and the remaining salt is in anhydrous form,

∴ Mass of anhydrous salt = 45.15 - 42.45 = 2.7 g

To find the molar mass of anhydrous salt of CuSO4,

atomic weight of Cu = 63.5 g

atomic weight of S = 32 g

atomic weight of O =16 g

∴ molar mass of anhydrous salt of CuSO4 = 63.5 + 32 + (16 ×3)

=159.5 gm

Learn more about molar mass here...

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5 0

2 years ago