What is the number of elements for Mg(OH)2.

Perform the calculation and record the answer with the correct number of significant figures.

kotykmax [81]

The question is incomplete, here is the complete question:

A. (6.5-6.10)/3.19

B. (34.123 + 9.60) / (98.7654 - 9.249)

Answer:

For A: The answer becomes 0.1

For B: The answer becomes 0.4884

Explanation:

Significant figures are defined as the figures present in a number that expresses the magnitude of a quantity to a specific degree of accuracy.

Rules for the identification of significant figures:

Digits from 1 to 9 are always significant and have infinite number of significant figures.
All non-zero numbers are always significant. For example: 664, 6.64 and 66.4 all have three significant figures.
All zeros between the integers are always significant. For example: 5018, 5.018 and 50.18 all have four significant figures.
All zeros preceding the first integers are never significant. For example: 0.00058 has two significant figures.
All zeros after the decimal point are always significant. For example: 2.500, 25.00 and 250.0 all have four significant figures.
All zeroes used solely for spacing the decimal point are not significant. For example: 10000 has one significant figure.

Rule applied for addition and subtraction:

The least precise number present after the decimal point determines the number of significant figures in the answer.

Rule applied for multiplication and division:

In case of multiplication and division, the number of significant digits is taken from the value which has least precise significant digits

For A: (6.5-6.10)/3.19

This a a problem of subtraction and division.

First, the subtraction is carried out.

$\Rightarow \frac{6.5-6.10}{3.19}=\frac{0.4}{3.19}$

Here, the least precise number after decimal was 1.

$\Rightarrow \frac{0.4}{3.19}=0.125$

Here, the least precise number of significant digit is 1. So, the answer becomes 0.1

For B: (34.123 + 9.60) / (98.7654 - 9.249)

This a a problem of subtraction, addition and division.

First, the subtraction and addition is carried out.

$\Rightarow \frac{34.123+9.60}{98.7654-9.249}=\frac{43.723}{89.5164}=\frac{43.72}{89.516}$

Here, the least precise number after decimal in addition are 2 and in subtraction are 3

$\Rightarrow \frac{43.72}{89.516}=0.48840$

Here, the least precise number of significant digit are 4. So, the answer becomes 0.4884

6 0

2 years ago

Write the chemical equation for the dissolution reaction of solid iron(iii) hydroxide in water. include the phases of all specie

Allushta [10]

When solid iron (iii) hydroxide is dissolved into water, it ionizes or it dissociates into ions. These ions are the iron (iii) ions and the hydroxide ions. Iron(III) oxide is classified as a base when in aqueous solution since it produces hydroxide ions. It is a weak base so it does not completely dissociate into the solution. The dissociation equation would be:

Fe(OH)3 <-----> Fe3+ + OH-

To write a complete reaction, the reaction should be balanced wherein the number of atoms of each element in the reactant side and the product side should be equal. Also, the phases of the substances should be written. We do as follows:


Fe(OH)3 (s) <-----> Fe3+ (aq) + 3OH- (aq)

4 0

3 years ago

How would a collapsing universe affect light emitted from clusters and superclusters? A. Light would acquire a blueshift. B. Lig

Lady_Fox [76]

Answer:

Choice A: Light would acquire a blueshift.

Explanation:

When a universe collapses, clusters of stars start to move towards each other. There are two ways to explain why light from these stars will acquire a blueshift.

Stars move toward each other; Frequency increases due to Doppler's Effect.

The time period $t$ of a beam of light is the same as the time between two consecutive peaks. If $\lambda$ is the wavelength of the beam, and both the source and observer are static, the time period $T$ will be the same as the time it takes for light travel the distance of one $\lambda$ (at the speed of light in vacuum, $c$ ).

$\displaystyle t = \frac{\lambda}{c}$ .

Frequency $f$ is the reciprocal of time period. Therefore

$\displaystyle f = \frac{1}{t} = \frac{c}{\lambda}$ .

Light travels in vacuum at a constant speed. However, in a collapsing universe, the star that emit the light keeps moving towards the observer. Let the distance between the star and the observer be $d$ when the star sent the first peak.

Distance from the star when the first peak is sent: $d$ .
Time taken for the first peak to arrive: $\displaystyle t_1 =\frac{d}{c}$ .

The star will emit its second peak after a time of. Meanwhile, the distance between the star and the observer keeps decreasing. Let $v$ be the speed at which the star approaches the observer. The star will travel a distance of $v\cdot t$ before sending the second peak.

Distance from the star when the second peak is sent: $d - v\cdot t$ .
Time taken for the second peak to arrive: $\displaystyle t_2 =t + \frac{d - v\cdot t}{c}$ .

The period of the light is $t$ when emitted from the star. However, the period will appear to be shorter than $t$ for the observer. The time period will appear to be:

$\begin{aligned}\displaystyle t' &= t_2 - t_1\\ &= t + \frac{d - v\cdot t}{c} - \frac{d}{c}\\&= t + (\frac{d}{c} - \frac{v\cdot t}{c}) -\frac{d}{c}\\&= t - \frac{v\cdot t}{c} \end{aligned}$ .

The apparent time period $t'$ is smaller than the initial time period, $t$ . Again, the frequency of a beam of light is inversely proportional to its period. A smaller time period means a higher frequency. Colors at the high-frequency end of the visible spectrum are blue and violet. The color of the beam of light will shift towards the blue end of the spectrum when observed than when emitted. In other words, a collapsing universe will cause a blueshift on light from distant stars.

The Space Fabric Shrinks; Wavelength decreases as the space is compressed.

When the universe collapses, one possibility is that clusters of stars move towards each other. Alternatively, the space fabric might shrink, which will also bring the clusters toward each other.

It takes time for light from a distant cluster to reach an observer on the ground. The space fabric keeps shrinking while the beam of light makes its way through the space. The wavelength of the beam will shrink at the same rate. The wavelength of the beam of light will be shorter by the time the beam arrives at its destination.

Colors at the short-wavelength end of the visible spectrum are blue and violet. Again, the color of the light will shift towards the blue end of the spectrum. The conclusion will be the same: a collapsing universe will cause a blueshift on light from distant stars.

8 0

2 years ago

Ammonia can be produced via the chemicalreaction

otez555 [7]

Answer:

3)The reaction is not at equilibrium and willproceed to the right.

Explanation:

The reaction quotient of an equilibrium reaction measures relative amounts of the products and the reactants present during the course of the reaction at particular point in the time.

It is the ratio of the concentration of the products and the reactants each raised to their stoichiometric coefficients. The concentration of the liquid and the gaseous species does not change and thus is not written in the expression.

Q < Kc , reaction will proceed in forward direction.

Q > Kc , reaction will proceed in backward direction.

Q = Kc , reaction at equilibrium.

Given that:

Q = $3.56\times 10^{-4}$

K = $6.02\times 10^{-2}$

Since, Q < K , reaction is not at equilibrium and will proceed to right, in forward direction.

3 0

2 years ago

¿que se necesita para escribir un informe de experimento? Plis

Ludmilka [50]

Answer:

Explanation:

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Hipótesis. La hipótesis consiste en una apreciación que el investigador hace en torno al problema. Se define como una...

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4 0

2 years ago

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