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3 years ago

How did Mendeleev organize the elements to create a periodic table

2 answers:

4 0

Mendeleev arranged the elements known at that time according to atomic mass. The elements were arranged in rows called periods, in increasing order. Each row had eight elements. He also arranged them accordingly in columns, where the elements in each column, called groups, had similar properties.

He left some blanks on his table because he predicted that the big gaps between some atomic mass' of elements indicated that there were other elements yet to be discovered that would fill in that gap. He was able to predict the atomic weights of some of the elements in between.

irga5000 [103]3 years ago

4 0

The answer is according to increase mass and similar properties

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How many minutes will it take you to finish a 5 km race at an average speed of 7.0m/s?

slava [35]

Answer:

11.9 minutes

Explanation:

The journey is 5000 meters long. The time it takes in seconds for the journey at this speed is 5000/7 =714 seconds.

714/60=time in minutes =11.9 minutes approximately.

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3 years ago

What distance was an object moved by a force of 40 N if the work was 600 joules

Westkost [7]

If a force of 40 N does 600 joules of work, then it must have been applied continuously through a distance of (600/40) = 15 meters .

We can't tell how far the object ultimately moved, because we don't know
what other forces may have been acting on it. If there were NO other forces,
then it just kept going, even after the 40-N force stopped, with the same
600 joules of kinetic energy that it got from the work that the force did.

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3 years ago

Read 2 more answers

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raketka [301]

0.520155077123917 i believe?? hope this helps

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3 years ago

_____ motion occurs when tectonic plates move apart from each other. A. Divergent B. Transform C. Convergent

Likurg_2 [28]

A. Divergent (pretty sure)

4 0

4 years ago

Read 2 more answers

An aluminum sphere is 8.55 cm in diameter. What will be it's % change in volume if it is heated from 30 C to 155 C?

Ghella [55]

We know that

• The sphere diameter is 8.55 cm.

• The temperature change is from 30 C to 155 C.

First, we have to find the radius of the sphere. The radius is the half diameter.

$\begin{gathered} r=\frac{d}{2}=\frac{8.55\operatorname{cm}}{2} \\ r=4.275\operatorname{cm} \end{gathered}$

Now we have to find the volume of the sphere using the following formula.

$V=\frac{4}{3}\pi(r)^3$

Where r = 4.275 cm.

$\begin{gathered} V=\frac{4}{3}\pi(4.275\operatorname{cm})^3 \\ V\approx327.26(cm)^3 \end{gathered}$

Then, we use the following formula

$V_2-V_1=BV_0(T_2-T_1)$

Where the initial volume is 327.26 cubic cm, B is a constant about thermal expansion for aluminum, and we have to find the final volume to then calculate the percentage change.

$\begin{gathered} \Delta V=75\times10^{-6}\cdot327.26(155-30) \\ \Delta V=75\times10^{-6}\cdot327.26(125) \\ \Delta V\approx3.07(cm)^3 \end{gathered}$

This means that the volume change is 3.07 cubic centimeters.

At last, we have to divide the volume change by the initial volume, and then we have to multiply it by 100% to express it as a percentage.

$\frac{\Delta V}{V_1}\times100=\frac{3.07}{327.26}\times100\approx0.938$ <h2>Therefore, the percentage change is 0.938%.</h2>

5 0

1 year ago