why is it called the periodic table of elements (why is the word periodic in it)

Answer:

Examples of measured numbers: The diameter of a coin, such as 10.2 mm. The weight of an object, such as 8.887 grams. The length of a pen, such as 12 cm.

Explanation:

Answer:

It completely depends on what you are measuring, what instrument you are using, and the uncertainty associated with your measurement.

Explanation:

When expressing a measurement, there is always going to be a part that you know, and a part that you guess. They both make up known numbers collectively called significant figures (commonly shortened to "sig figs"). For instance, imagine you are measuring the length of a pencil. Let's say it is a typical ruler with divisions of 0.1 cm (picture for reference). You measure the pencil, and to your eyes it looks like it is about 9 cm and 5 small tick marks (so, 0.5 cm), so we'll call that 9.5 cm. Now, this is a known value, so you are certain that it is a least 9.5 cm. However, it may be true that there is one more decimal place that can be known. The general rule is that you want to add one more uncertain digit to the rightmost side of the number, and how many digits depends on the divisions of the instrument. Our ruler has divisions of 0.1 cm (the small tick marks), and so we will go one more place out, and add another digit. Now, let's say our eyes are pretty good, so let's say it's 9.5 cm, and then add that one uncertain digit, a 0 to the smallest division of 0.1, so, 0.10. The final measurement we record is 9.50 cm. Now, it may seem like we are simply guessing or even being unreasonable in our assessment of how long this pencil is. I can promise you that not knowing the actual measurement of this pencil will not make a spaceship crash because of a specification that was not the "right measurement". For those life-or-death measurements, much more precise measurement machines are used; this is just a pencil. Also, it would be unreasonable to say that it is 9.500000 cm or 9.500001 cm. We do not have that kind of certainty with this ruler, only divisions of 0.1 cm, so we can only estimate out to one more decimal place.

In short, find the smallest division of a ruler or whatever device (like a chemical beaker) you are using, and then add one uncertain digit to the end of that. If it's 0.1 cm, then add one digit to that. (example: 5.6 --> 5.63; 3 because that is what it looks like on the ruler). If it's 1 cm, then add an extra .1, so the measurement is 1.1 cm. And of course, it's not always cm you are using, that was just an example. Best of luck!

1

Explanation:

because they period two

Answer:

1

Explanation:

Answer:

For, Aluminum chloride, aluminum = AL+ so here aluminum is the cation

But Chloride is the anion = CL -

So cation is positive and anion is negative

Answer:

no

Explanation:

Answer:

In both natural and built systems, stability and change are an important focus of study for both scientists and engineers. Stability refers to a system that is unchanging. ... A dynamic equilibrium exists when chemical reactions or physical movements occur at rates that balance out, creating no net change in a system.

Answer:

In both natural and built systems, stability and change are an important focus of study for both scientists and engineers. Stability refers to a system that is unchanging. ... A dynamic equilibrium exists when chemical reactions or physical movements occur at rates that balance out, creating no net change in a system.

Explanation:

Answer:

a)6.730×10⁻⁴

b)5×10⁴

c)3.010×10⁻⁶

d)1.3240×10²

e)2.232×10³

The given numbers in scientific notation are [tex]6.730 \times 10^{-4}[/tex], [tex]5.0 \times 10^4[/tex], [tex]1.3240 \times 10^2[/tex],  [tex]2.232 \times 10^3[/tex] and  [tex]2.232 \times 10^3[/tex], respectively.

Scientific notation is a way of expressing very large or very small numbers in a compact and convenient form.

To express a number in scientific notation, we need to write the number in the form: [tex]\rm a\times 10^b[/tex]

a) 0.0006730 can be written in scientific notation as [tex]6.730 \times 10^{-4}[/tex]. The decimal point was moved 4 places to the right, so the exponent is negative 4.

b) 50000.0 can be written in scientific notation as [tex]5.0 \times 10^4[/tex]. The decimal point was moved 4 places to the left, so the exponent is positive 4.

c) 0.000003010 can be written in scientific notation as [tex]3.010 \times 10^{-6}[/tex]. The decimal point was moved 6 places to the right, so the exponent is negative 6.

d) 132.40 can be written in scientific notation as [tex]1.3240 \times 10^2[/tex]. The decimal point was moved 2 places to the left, so the exponent is positive 2.

e) 2232 can be written in scientific notation as [tex]2.232 \times 10^3[/tex]. The decimal point was moved 3 places to the left, so the exponent is positive 3.

Therefore, [tex]6.730 \times 10^{-4}[/tex], [tex]5.0 \times 10^4[/tex], [tex]1.3240 \times 10^2[/tex],  [tex]2.232 \times 10^3[/tex] and  [tex]2.232 \times 10^3[/tex], are the scientific notation for the given numbers.

Learn more about Scientific notation here:

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Answer:

5.14mole

Explanation:

Given parameters:

Mass of sodium bicarbonate  = 431.56g

Unknown:

Number of moles  = ?

Solution:

To find the number of moles, we use the expression below:

  Number of moles  = [tex]\frac{mass}{molar mass}[/tex]  

 Molar mass = 84.01g/mol

 Number of moles  = [tex]\frac{431.56}{84.01}[/tex]   = 5.14mole

Answer:

84 pt =__50.4399___ qt

5.0 gal =___18.9271__ L​

Explanation:

Have A Wonderful Day!!

Answer: 84 pints = 42 quarts

5.9 gallons = 1.89271

Explanation:

Explanation:

The amount of rainfall would have the greatest impact on the amount of water available for people in this area. The more the rainfall the more water soaks through layers of porous rocks.Hence, level of water table will remain sufficient for easy pumping of water to the homes.Texas receives plenty of rainfall in a year.In a single year the region can receive up to 48 inches (1,200 mm) of precipitation, and flooding is common near rivers and in low-lying areas. Therefore water table remains intact throughout the year.

Answer:

63.6%

Explanation:

The given compound is:

     N₂O;

The problem here is to find the percent composition of nitrogen in the compound.

First find the molar mass of the compound:

 Molar mass of N₂O = 2(14) + 16  = 44g/mol

So;

 Percentage composition of Nitrogen  = [tex]\frac{2 x 14}{44}[/tex]  x 100  = 63.6%

Answer:

[(x-37.5)/x]*100%

62.5%  (assuming the original sample weighs 100.0g)

Explanation:

Let's say that the original sample is x

Mass of I-125 which has decayed: x-37.5

Percentage of decayed mass: [(x-37.5)/x]*100%

Please recheck, for this may not be the correct answer

Answer:

B. Mass in motion. Is the definition of momentum

Answer:

A

Explanation:

In simple terms: Hammer goes one way, air goes the other way.

Answer:

d

Explanation:

i took the test

Answer:

combustion

Explanation:

your welcome :)

Answer:

Mass = 824.57 g

Explanation:

Given data:

Mass of bromine = ?

Number of moles of bromine = 5.16 mol

Solution:

Formula:

Mass = number of moles × molar mass

Molar mass of bromine = 159.8 g/mol

by putting values,

Mass = 5.16 mol × 159.8 g/mol

Mass = 824.57 g

Answer:

c! Hope this helps!

Explanation:

BRAINLIEST PLZ ;)

Answer:

I think its the third one im not sure tho

Explanation:

Answer:

The symbol that represent a salt is CaCl2

Explanation:

The CaCI2 is the calcium chloride that an organic compound now a salt having a chemical formula i.e. CaCI2. Also it is non-color cyrstalline solid at the room temperature also it is highly soluble in the water

Therefore as per the given situation the symbol that represent a salt is CaCI2

This is the answer and the same is not provided in the given options

Answer:

the third one because oceans don't affect the weather  

Explanation:

Answer:

A Infiltration

Explanation:

The downward movement of water through pore spaces and other spaces in soil due to gravity is called infiltration.

Infiltration is greatly due to the force of gravity forcing water through pore spaces downward.

Answer:

B. Water quality

Explanation:

Answer:

3.81 [tex]\frac{1}{74.55}[/tex] X [tex]\frac{6.02*10^{23} }{1}[/tex] = 3.08 X 10^22

Explanation:

74.55 is the mass

Answer:

The pair of arrows which represents the relationship of speeds of the two cars is;

The second option as shown in the attached drawing

Explanation:

The given parameters are;

The reading on the speedometer of one car = 20 m/s

The reading on the speedometer of the other car = 72 km/h = 20 m/s

The blue arrow = 20 m/s

Therefore, given that the speeds of both cars are equal (20 m/s = 72 km/h = 20 m/s),  the pair of arrows that represent the relationship of speeds of the two cars is two equal length blue arrows which is the second option

The attached diagram showing the pair of arrows that represents the relationship of speeds of the two cars is drawn using Microsoft Visio.

Answer:

The first question is option 2

and the second question in option 1

Explanation:

Answer:

hey :)

your answer is D.

Explanation:

To find density, you must divide mass and volume.

8 divided by 4 is 2

6 divided by 6 is 0

4 divided by 2 is 2

hope i helped any :))

Answer:

The skin of the apple is very thin, and the crust of the Earth is very thin.

Answer:

Alkenes contain a double bond that is composed of one sigma and one pi bond between two carbon atoms. The sigma bond has similar properties to those found in alkanes , while the pi bond is more reactive. The carbon atoms in the double bond are sp² hybridized , forming a planar structure.

Explanation:

Believe it!!!

Answer:

12

Explanation:

Answer:

Fluorine gas reacts violently with water to produce hydrogen fluoride and ozone according to the following unbalanced equation. How many moles of o, are created assuming STP conditions are in effect, given

Explanation:

3