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Fofino [41]
3 years ago
10

How many periods does the modern periodic table have?

Chemistry
1 answer:
dusya [7]3 years ago
8 0
There are 7 periods in the modern periodic table

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What volume of a 6.0m hcl solution is required to make 250.0 milliters of 1.5 m hcl
Georgia [21]

Answer : The volume for 6.0m HCl solution required = 62.5 ml

Solution : Given,

Initial concentration of HCl solution = 6.0m

Final concentration of HCl solution = 1.5m

Final volume of HCl solution = 250 ml

Initial volume of HCl solution = ?

Formula used for dilution is,

M_1V_1=M_2V_2

where,

M_1 = initial concentration

M_2 = final concentration

V_1 = initial volume

V_2 = final volume

Now put all the given values in above formula, we get the initial volume of HCl solution.

6.0m\times V_1=1.5m\times 250ml

V_1 = 62.5 ml

Therefore, the volume for 6.0m HCl solution required = 62.5 ml


8 0
3 years ago
What is a problem that would likely occur if two cultures had different calenderars
aksik [14]
The Sun, Moon, and stars have helped people for thousands of years. When you look into the sky, you will notice that they follow certain patterns. This happens most of the time, but not all of the time. Since most patterns repeat over and over, they have helped us keep track of time. These patterns have also helped us make calendars. Making calendars was a difficult task. Our ancestors had to decide on the length of a year. Also, they had to decide on the length of a day. As you know a day takes 24 hours. That is the time that Earth takes to rotate once on its axis. A year is longer and takes 365 days. This length of time is related to the time that it takes for Earth to go around the Sun. However, this is not exactly true. Earth’s trip takes 365 days – plus a fraction of another day. This is what complicates our calendar. We have been able to solve this problem by adding an extra day in the month of February. Most often, you will see that February has 28 days. Every four years, February has one extra day. During this year we end up with 29 days in this month. When this happens, the year is called a Leap Year. It helps us keep our calendar in order. Deciding on the length of a month has also been a challenge. Some cultures around the world have used a lunar calendar. A lunar calendar is based on the Moon’s cycle. The Moon takes 29 and one-half days to complete one cycle. Then things got a lot harder. Different cultures start their months at a different time of the Moon’s cycle. For example, the Hebrew and Islamic calendars start their months when a crescent moon is seen in the sky. The Chinese start their new months at the new moon phase. These differences have made it harder for cultures to communicate. Trading with one another has also been hard for this reason. As time went by, most countries began to use the same calendar. When this happened in the twentieth century, trade and communication became a lot easier. Some countries decided to drop thirteen days from their calendar. This is because their old way of counting did not match up with the new way. England had problems with the calendar back in the 1500s. The English decided to divide their calendar into months. Each month had four weeks. By doing this, one week ended up being longer than seven days. Also, this resulted in thirteen months to a yea
3 0
4 years ago
Read 2 more answers
When pure methanol is mixed with water the resulting solution feels warm would you expect this solution to be ideal?Explain
Pepsi [2]

Answer:

No

Explanation:

In ideal solutions, the interactions between solute - solvent are approximately the same as those of solute - solute and solvent - solvent, that is the interactions are to be practically indistintiguishable after disolution.

The moment we have a release of energy (the solution feels warm) we are to conclude that there are strong interactions between the water and methanol molecules so we would expect the solution to be non ideal.

The reason for the interactions is the presence of hydrogen bonds between methanol and water.

5 0
3 years ago
If a certain gas occupies a volume of 19 L when the applied pressure is 9.5 atm, find the pressure when the gas occupies a volum
kakasveta [241]

Answer: 37.6 atm

Explanation:

Given that,

Initial volume of gas (V1) = 19L

Initial pressure of gas (P1) = 9.5 atm

Final volume of gas (V2) = 4.8L

Final pressure of gas (P2) = ?

Since pressure and volume are given while temperature remains the same, apply the formula for Boyle's law

P1V1 = P2V2

9.5 atm x 19L = P2 x 4.8L

180.5 atm•L = 4.8L•P2

Divide both sides by 4.8L

180.5 atm•L/4.8L = 4.8L•P2/4.8L

37.6 atm = P2

Thus, the final pressure is 37.6 atmospheres.

3 0
3 years ago
HELP ITS DUE IN 10 MIN How long will it take an object to move 100 meters if the object is traveling with an average
tiny-mole [99]

Answer:

Would it be<em><u> 7.69 seconds</u></em>?

Explanation:

5 0
3 years ago
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