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2 years ago

How do you find the significant figure of 505kg-450.25kg

Chemistry

1 answer:

horrorfan [7]2 years ago

6 0

Answer:

4 significant figures

Explanation:

505 has 3 significant figures

450.25 has 5 significant figures

First do simple subtraction

505 - 450.25 =54.75

And then evaluate any number that has significance or is important if the decimal were to be moved.

4 significant figures

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What is an element? Arrow

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Answer:

One arrow is positioned in each box according to Hund's Rule which tells us to maximise the number of unpaired electrons in orbitals of the same subshell, and, to give those electrons the same "spin" (parallel spin).

Explanation:

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1 year ago

Science / which phrase describes the differences between these two liquid ?

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Answer:

viscosity

Explanation:

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2 years ago

Why can some metals be extracted from compounds by heating with carbon and why can some not

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Answer:

Some metals can be extracted from compounds by heating with carbon atom because they are less reactive than carbon and some metals cannot be extracted because they are more reactive than carbon atom.

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3 years ago

In a certain industrial process involving a heterogeneous catalyst, the volume of the catalyst (in the shape of a sphere) is 10.

olga nikolaevna [1]

Answer:

a. The second run will be faster.

d. The second run has twice the surface area.

Explanation:

The rate of a reaction is proportional to the surface area of a catalyst. Given the volume (V) of a sphere, we can find its surface area (A) using the following expression.

$A=\pi ^{1/3} (6V)^{2/3}$

The area of the 10.0 cm³-sphere is:

$A=\pi ^{1/3} (6.10.0)^{2/3}=22.4cm^{2}$

The area of each 1.25 cm³-sphere is:

$A=\pi ^{1/3} (6. 1.25)^{2/3}=5.61cm^{2}$

The total area of the 8 1.25cm³-spheres is 8 × 5.61 cm² = 44.9 cm²

The ratio of 8 1.25cm³-sphere to 10.0 cm³-sphere is 44.9 cm²/22.4 cm² = 2.00

Since the surface area is doubled, the second run will be faster.

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2 years ago

The painkiller, Advil® contains the active ingredient ibuprofen (IB), which has a pKb of

denis23 [38]

This problem is providing the basic dissociation constant of ibuprofen (IB) as 5.20, its pH as 8.20 and is requiring the equilibrium concentration of the aforementioned drug by giving the chemical equation at equilibrium it takes place. The obtained result turned out to be D) 4.0 × 10−7 M, according to the following work:

First of all, we set up an equilibrium expression for the given chemical equation at equilibrium, in which water is omitted for it is liquid and just aqueous species are allowed to be included:

$Kb=\frac{[IBH^+][OH^-]}{[IB]}$

Next, we calculate the concentration of hydroxide ions and the Kb due to the fact that both the pH and pKb were given:

$pOH=14-8.20=5.80$

$[OH^-]=10^{-5.8}=1.585x10^{-6}M$

$Kb=10^{-5.20}=6.31x10^{-6}$

Then, since the concentration of these ions equal that of the conjugated acid of the ibuprofen (IBH⁺), we can plug in these and the Kb to obtain:

$6.31x10^{-6}=\frac{(1.585x10^{-6})(1.585x10^{-6})}{[IB]}$

Finally, we solve for the equilibrium concentration of ibuprofen:

$[IB]=\frac{(1.585x10^{-6})(1.585x10^{-6})}{6.31x10^{-6}}=4.0x10^{-7}$

Learn more:

(Weak base equilibrium calculation) brainly.com/question/9426156

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2 years ago