How has the human population changed during the past 50 years

Answers

Answer 1

Answer:

The human population has increased by the billions, and we have been creating better and more complex technology over the years. So, overall there is a difference between now and 50 years ago.


Related Questions

In Raoult’s law, what happens to the partial pressure of the solution when the mole fraction of the solvent increases?

Answers

Answer: c. it increases

Explanation:

True or false. The particulates left from combustion have the same mass as the substance that was burned. Giving Brainliest!

Answers

I hope this helps have a good day

The study of chemicals is called chemistry.

The correct answer is true.

What is combustion?The process of burning anything in the presence of oxygen is called combustion.

According to the question, the statement is right because the solid amount is converted into the gas after burning but the mass remains constant.

law of conservation of massit states that the mass of the element remains constant before and after the reaction.

Hence, the correct answer is true.

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Please help me i am very lost
Calculate the salinity of the liquids in the table. Round your answers to one decimal place.
$\frac{\text{mass of salt}\left(g\right)}{\text{mass of solution}\left(g\right)}\times1000=salinity\left(ppt\right)$mass of salt(g)mass of solution(g) ×1000=salinity(ppt)


Sample Solution Mass of Salt (g) Mass of Solution (g) Salinity (ppt)
A

27

1000

B

15

850

C

94

2355

D

11

3796

Answers

Answer:

i think that's number D.

the mass of 0.0321 moles of Ca (CN)2

Answers

The mass of Ca(CN)2 : 92,11 g/mol

Further explanation

Given

0.0321 moles of Ca(CN)2

Required

The mass

Solution

The mole is the number of particles contained in a substance

1 mol = 6.02.10²³

Moles can also be determined from the amount of substance mass and its molar mass

mol(n) = mass(m) : MW(molecular weight)

Input the value :

mass = mol x MW Ca (CN)2

mass =  0.0321 x 92,11 g/mol

mass = 2.957 g

H2o is initially present in a state where its molecules are far apart. During a change of state, its molecules slow down. Which change of state has most likely taken place?
from a gas to a liquid
from a liquid to a gas
from a solid to a liquid
from a gas to a plasma

Answers

Answer: from a gas to a liquid

Explanation:

The change of state that has most likely taken place is from a gas to a liquid, where the molecules slow down and move closer together due to a decrease in temperature or an increase in pressure.

What are states of matter?

Matter is anything that occupies space and has mass. The three fundamental states of matter are solid, liquid, and gas. Solids have a definite shape and volume, with tightly packed molecules that vibrate in place. Liquids have a definite volume but no definite shape, with molecules that can slide past one another.

Gases have neither a definite shape nor a definite volume, with molecules that are widely separated and move freely in all directions. A fourth state of matter, plasma, also exists and is formed at extremely high temperatures or by ionizing a gas. In plasma, electrons have separated from their nuclei to form a cloud of charged particles.

Other, more exotic states of matter have also been observed under extreme conditions, such as Bose-Einstein condensates and quark-gluon plasma.

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You are making a temperature measurement with a lab thermometer. The increments (markings) are 1°C. You see that the temperature is about 1/3 of the way from 21°C to 22°C. How would you record this temperature? How many significant figures does it have? In what place value is the smallest certain digit? In what place value (tens, ones, tenths, etc.) is the uncertain digit?

Answers

Answer: 21.3, 3 sig figs, units certain, tenths uncertain

Explanation:

The temperature is 21.3 degrees Celsius, This temperature has 3 significant figures. The smallest certain digit is in the tenth place and the uncertain digit is in the decimal place.

What are significant figures?

The number that is given as digits is established using significant figures. A meaningful representation of numbers is carried by these digits. Frequently, significant numbers are employed in place of figures. By counting all of the values beginning with the first non-zero digit on the left, we may determine the number of significant digits. 12.45, for instance, contains four significant numbers.

Therefore, in the above observation, the temperature is 21.3 degrees Celsius, This temperature has 3 significant figures. The smallest certain digit is in the tenth place and the uncertain digit is in the decimal place.

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How many moles of iron (Fe) will be produced from 6.20 moles of carbon monoxide (CO) reacting with excess iron (III) oxide (Fe2O3)?​

If you can, please show the work because I really don't understand and ya girl is struggling. thank you guysss <33

Answers

Answer:

4.13 moles of Fe

Explanation:

Step 1: Write the balanced equation

3 CO + Fe₂O₃ ⇒ 2 Fe + 3 CO₂

Step 2: Establish the appropriate molar ratio

According to the balanced equation, the molar ratio of CO to Fe is 3:2.

Step 3: Calculate the moles of Fe formed from 6.20 moles of CO

We will use the previously established molar ratio.

6.20 mol CO × 2 mol Fe/3 mol CO = 4.13 mol Fe

The mass number of an atom is determined by ___.

1.adding the protons and electrons
2.adding the protons and neutrons
3.adding the electrons and neutrons
4. adding the protons,electrons and neutrons

Answers

2: protons and neutrons

If the common element of Fluorine-9 and one of the isotopes is Fluorine-10, what does the -10 tell us about the element and how many protons and neutrons does the element have?

Answers

flourine have 9 proton

19 neutrons and 9 electron

mark be a brain list

8. The size and shape of an object are some of its....

Answers

Answer:

Characteristics...

Explanation:

I hope that's right, if not super sorry. I'm not the smartest. I tried my best if it's wrong

CuBr(s)⇄Cu+(aq)+Br−(aq)

Shown above is the chemical equation for the dissolution of the slightly soluble salt CuBr(s). Its Ksp value in pure water was experimentally determined. CuBr was found to be much less soluble in a 0.001MNaBr solution than in pure water. Which of the following correctly explains the decrease in solubility of CuBr in 0.001 M NaBr?

A.)The concentration of water is much less in the NaBr solution than in pure water, reducing the rate of dissolution of the salt.
B.)The presence of Na+ ions in the solution inhibits the dissolution of salts.
C.)The presence of additional Br− already in the solution decreases the value of the Ksp for CuBr , causing the solubility to decrease.
D.)The presence of additional Br− ions already in the solution means equilibrium will be reached when much less CuBr has dissolved.

Answers

Answer:

D) The presence of additional Br- ions already in the solution means equilibrium will be reached when much less CuBr has dissolved.

Explanation:

CuBr ⇄ [tex]Cu^+[/tex] + [tex]Br^-[/tex]

Because there is Br- in CuBr, when put into solution, those Br- ions become part of the products side of the equation, shifting the equilibrium back towards the CuBr side, meaning less CuBr will dissolve.

The decrease in the solubility of the CuBr in NaBr solution has been due to the presence of additional Br ions in the solution. Thus option C is correct.

The equilibrium position has been the condition when the concentration of the reactants and products has been equal. The solubility of the CuBr has been dependent on the ksp for the solution.

The ksp has been the solubility product and has been dependent on the concentration of the reactants. The NaBr solution will be dissociated in the form of Na ions and Br ions. The dissolution has been based on the equilibrium of the CuBr.

With the presence of additional Br ions, the equilibrium of the CuBr solution has been reached earlier, and thereby the solubility of the solution has been decreased.

The decrease in the solubility of the CuBr in NaBr solution has been due to the presence of additional Br ions in the solution. Thus option C is correct.

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How often is Earth's surface being changed?

1 every hundred years
2 never
3 at all times
4 once a year

Answers

Answer:

I believe it is 3.

Explanation:

because the earth is constantly shifting.

It is changing all the time.

The Earth's surface is constantly changing.
3

PLEASE HELP
What heat transfer is a Heater.

Answers

Answer:

All electric heaters make use of one or more of the fundamental heat transfer mechanisms – namely convection, conduction, or radiation.

For regular...

Conduction is heat transfer by direct contact, like frying an egg. Convection is heat transfer by the movement of gases or liquids, like most home furnaces, clothes dryers, or car heaters. Radiation is the transfer of heat in waves through space, like the sun or a fire.

chemical equation for cycloheptane (l)

Answers

Answer: C7H14 - PubChem.

Explanation:

The average weather conditions affecting a biome is called ____.

precipitation

tundra

temperate condition

Climate

Answers

the answer is: climate

how many oxygen atoms are in 1 mol of CO2

Answers

Answer:  2 atoms

Explanation: A molecular formula of the compound carbon dioxide is CO 2 . One molecule of carbon dioxide consists of 1 atom of carbon and 2 atoms of oxygen.

Why can a solution be classified as a mixture?


Both are always homogeneous.


It is made up of only one substance.


Both are made up of two substances that are not chemically combined.


Both are made up of two substances that are chemically combined.

Answers

Answer:

Both are made up of two substances that are not chemically combined.

Explanation:

Solutions can be classified as a mixture because both are made up of two substances that are not chemically combined.

A mixture is made up of the following properties:

They have an indefinite composition. Their constituents retain their physical properties. They can easily be separated into their physical constituents.

Solutions share this property with all mixtures.

The constituent of a solution are not chemically combined or bonded together

Answer:

c

Explanation:

I go to k12 (or you) If you go to k12 this is correct

5. Identify each of the following as an element, a mixture, or a compound.
a. aluminum foil
b. air
C. water
d. salt water
e. copper
wire
f. steel

Answers

Answer:

Aluminum foil ~ element

Air ~ mixture

Water ~ compound

Salt Water ~ mixture

Copper Wire ~ element

Steel ~ element

WILL GIVE BRAINLIEST


at which distance from refrigerator door would a magnetic force of attraction be weakest

A 7cm
B 3cm
C 1cm
D 10cm

Answers

Answer:

10 cm

Explanation:

because the magnetic force of attraction becomes weaker from a greater distance.

Answer:

D 10cm

Explanation:

As the distance between the two objects(magnet and Ferromagnetic Metals and Alloys) increases the magnetic for will decrease

if a iron nail is kept 1cm far from a magnet then the magnet will atract it easily but if the same iron nail is kep 3cm far from the magnet then the magnet won't attract it easily .

(Ferromagnetic materials such as iron, nickel and cobalt are attracted to magnets, as well as rare-earth metals like gadolinium, neodymium and samarium.)

Hope you've understood

Polar air masses bring warm temperature and have lower air temperature? T or F

Answers

Answer:

t? im pretty sure have a good day

Which of the following is not a chemical change?
a. paper being shredded
b. steel rusting
c. charcoal burning
d. a newspaper yellowing in the sun

Answers

Answer:

paper being shredded

Explanation:

Answer:

its A

Explanation:

would you consider alcohol as food nutrient? explain.​

Answers

Answer:

Explanation:

No I would consider it a drug

Alcohol is considered a drug and doesn't fall under the category of food nutrients.

What is alcohol?

Alcohol is a drink that contains ethanol. It is a type of alcohol that acts as a drug and is formed by the fermentation of fruits, grains, or sources of sugar.

Alcohol is classified as a depressant which means it slows down vital functions resulting in unsteady movement, slurred speech, and an inability to react quickly.

Alcohol overdose creates even more painful, depressant effects such as toxicity where the body vomits the poison, and finally unconsciousness,  coma, or death. These reactions depend upon the quantity of consumption of alcohol and how quickly.

Alcohol is a drug that damages a person’s ability to think rationally and distorts his judgment. Alcohol affects the mind, so it can never be considered nutritious food.

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HELPP nowww plssss!!!!

Answers

the answer is #2: gas

53.0 g of silver (1) nitrate reacts according to the reaction shown below:
AgNO3 + KCI — AGCI + KNO3
Find the theoretical yield of AgCl. If the amount of AgCl actually produced is 38.5 grams,
what is the percent yield of the experiment?

Answers

Answer:

Percent yield = 86.09%

Theoretical yield of AgCl = 44.72 g

Explanation:

Given data:

Mass of silver(1) nitrate = 53.0 g

Actual yield of AgCl = 38.5 g

Theoretical yield of AgCl = ?

Percent yield = ?

Solution:

Chemical equation:

AgNO₃ + KCl    →   AgCl + KNO₃

Number of moles of AgNO₃:

Number of moles = mass/molar mass

Number of moles = 53.0 g/ 169.87 g/mol

Number of moles = 0.312 mol

now we will compare the moles of AgNO₃ and AgCl

               AgNO₃         :           AgCl

                   1               :                1

                0.312          :           0.312

Theoretical yield of AgCl:

Mass = number of moles × molar mass

Mass = 0.312 mol × 143.32 g/mol

Mass = 44.72 g

Percent yield:

Percent yield = (actual yield / theoretical yield) × 100

Percent yield = ( 38.5 g / 44.72 g ) × 100

Percent yield = 86.09%

helpppp nowww plsss!!

Answers

Answer:

Solar energy.

Explanation:

Solar Energy,

Renewable sources are those, which can be used again and again so, solar energy is the answer.

What is the air we breathe composed of?

Answers

Answer:

oxygen

Explanation:

Are theories always Correct?​

Answers

Answer:

no, theories are not always correct

Section
1
2
7)
Given the equation representing a reaction:
203Pb + 5921 TECn + on
3
4
5
Which type of reaction is represented by this equation?
6
A)
neutralization
8
-9
B)
polymerization
C)
substitution
10
11
12
13
= 14
- 15
16
-17
D)
transmutation
18
19
20
21

Answers

Answer:

a

Explanation:

neutalize acidity level

when a liquid is cooled the kinetic energy of the particles a)decrease b) increase c) stay the same​

Answers

Answer:

a) decrease

Explanation:

Hope this will help

How many moles are there in 100 grams of carbon dioxide?

Answers

Answer:

there are 8.3259093974539 moles in 100 grams of carbon dioxide

The number of moles that are in 100 grams of carbon dioxide is 2.272 g/mol. Moles can be calculated by dividing the mass by the molar mass of the compound.

What are moles?

"The mole is a SI unit of measurement that is used to calculate the quantity of any substance."

The molar mass of many compounds can be calculated by dividing the mass of the compound by the number of moles of the compound. Mass is the quantity of matter of a physical body. The product of the molar mass of the compound and the moles of the substance are defined as mass.

Moles = mass / molar mass

The mass of carbon dioxide is 100 grams

The molar mass of carbon dioxide is 44.01 g/mol

Put the values in the formula of moles:

100 / 44.01 =  2.272 g/mol

Therefore, there are 2.272 g/mol of moles in 100 grams of carbon dioxide.

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