why is water considered a pure substance?

a. each water molecule is identical

b. water can be broken down by physical means

c. water molecules are made up of different types of atoms

d. water can be combined with other substances by physical means

heLp ​

Answers

Answer 1
um i think its A or C

Related Questions

Why does the rate of dissolution for a gas decrease as the temperature of a solvent increases?


more space for the solute to escape


less space for the solute molecules


less space between solvent molecules


more collisions between solute and solvent molecules

Answers

Answer:

As the kinetic energy of the gaseous solute increases, its molecules have a greater tendency to escape the attraction of the solvent molecules and return back to the gas phase. As a result, the solubility of a gas decreases as the temperature increases.

Explanation:

13. The quality of petrol as an engine
fuel improves with a higher amount
of
A. branched chain alkanes.
B. branched chain alkenes.
C. branched chain alkynes.
D. straight chain alkynes.
E. straight chain alkynes.​

Answers

Answer:

The correct option is;

A. Branched chain alkanes

Explanation:

By the process of cracking of petroleum, higher quality petrol are formed by converting straight chain petrol to branched petrol, which are the grade of petrol that burns more smoothly and therefore efficiently within internal combustion engines

The cracking process includes;

a) The conversion of alkanes which are large molecules into branched octanes

b) The conversion of alkanes with straight chain into branched chain alkanes

c) The formation of a branched chain alkane and an alkene from straight chain alkanes

d) The formation of branched chain alkane and hydrogen gas from a straight chain alkane.

why sodium and chlorine are active element​

Answers

It takes more energy to remove an electron from a sodium atom to form an Na+ ion than we get back when this electron is added to a chlorine atom to form a Cl- ion.

1. Solve for x

Atomic number 31

Atomic mass x

Number of protons y

Number of neutrons 33

Number of electrons 28

Charge of element z

Answers

Answer:

Atomic mass = proton + neutron

31+33= 64

Number of proton = Atomic number = 31

Charge of element is +3

Explanation:

A 20 N object is placed on a surface and starts to slide. What is the MOST likely reason the object begins to move?
A O Gravity exerts a balanced force on the object.
В.
Friction is applied to the object.
c. An unbalanced force causes acceleration.
D
The forces acting on the object are in equilibrium.


Answers

Answer:

c.

Explanation:

If the object starts to slide it must be on a slope.

There are 2 forces acting on the object - gravity and the friction between the object and the surface.

If sliding starts then the forces must be unbalanced.

The force of gravity is greater than the friction.

Answer:c

Explanation:

Para preparar 1 kilogramo de arcilla se requieren 400 gramos de agua. Si a nivel del laboratorio solo se cuenta con una probeta y sabemos que la densidad del agua es 1100Kg/m3 ¿Cuántos litros de agua se deben añadir?

Answers

Answer:

0.364 L

Explanation:

Para resolver este problema es necesario expresar la densidad en g/L.

Para hacer esa conversión primero convertimos m³ en L:

1 m³ = 1000 L1100 [tex]\frac{kg}{m^3}* \frac{1m^3}{1000L}[/tex] = 1.1 kg/L

Y después convertimos kg en g:

1.1 kg/L * [tex]\frac{1000g}{1kg}[/tex]= 1100 g/L

Finalmente dividimos la masa deseada (400 g) entre la densidad, para calcular el volumen:

400 g ÷ 1100 g/L = 0.364 L

How much radium-226 will remain from a 20 gram sample after 4800 years?

Answers

Answer:

2.5 g mass of Ra-226 will remain after 4800 years.

Explanation:

Given data:

Mass of Ra-226 = 20 g

Sample remain after 4800 years = ?

Solution:

Half life of Ra-226 = 1600 years

Number of half lives passed = T elapsed / half life

Number of half lives passed = 4800 year / 1600 year

Number of half lives passed = 3

At time zero = 20 g

At first half life = 20 g/2 = 10 g

At 2nd half life = 10 g/2 = 5 g

At 3rd half life = 5 g/2 = 2.5 g

Thus, 2.5 g mass of Ra-226 will remain after 4800 years.

a school bus drives 35 mph down the street and slows as it approaches the stop sign

Answers

acceleration i belive

Do you think it would be a good idea for a bumper car ride to have minimum and maximum weight requirements for riders? Apply Newton's second and third laws of motion in your response.

Answers

Answer: If only max or min yes but if we have min and max that is a bad idea it is not as safe.

why is a frozen popsicle a homogeneous mixture and not a pure substance ​

Answers

Answer:

You can not see the sugar.

Explanation:

Which has a higher frequency: microwaves or blue light? How do you know?​

Answers

Answer:

Microwaves

Explanation:

Microwaves have more energy than blue light

Among microwaves or blue light, blue light has a higher frequency. This is because blue light belongs to the visible region has a short wavelength and produces a higher amount of energy.

What is the relationship between frequency and wavelength?

The frequency of any wave is inversely related to the wavelength. This means that when the frequency of the wave increases, the wavelength decreases. While the relationship between frequency is directly related to the energy.

According to the context of this question, gamma rays have the highest frequency and shorter wavelength, while radiowaves have a shorter frequency and the highest wavelength.

Therefore, blue light has a higher frequency. This is because blue light belongs to the visible region has a short wavelength and produces a higher amount of energy.

To learn more about the Frequency of waves, refer to the link:

https://brainly.com/question/16610625

#SPJ2

when it is cold in your house

Answers

Answer:

yep.

Explanation:

I love to wear oversized hoodies and I get soft comfy blankets and watch movies. Have a nice night! :)

How many grams of calcium are made up by 2.68 x 1023 atoms?

Answers

Answer:

Mass = 17.8 g

Explanation:

Given data:

Number of atoms of Ca = 2.68 × 10²³

Mass in gram = ?

Solution:

Avogadro number:

The given problem will solve by using Avogadro number.

It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.

The number 6.022 × 10²³ is called Avogadro number.

1 mole = 6.022 × 10²³ atoms

2.68 × 10²³ atoms × 1 mole  /6.022 × 10²³ atoms

0.445 mol

Mass in gram;

Mass = number of moles ×  molar mass

Mass = 0.445 mol  ×  40 g/mol

Mass = 17.8 g

3. Calculate the number of moles and mass in
gram_of_1 x 10^20mdecules of Nz gas
.​

Answers

Answer:

0.17×10⁻³ mol

Mass = 0.00476 g

Explanation:

Given data:

Number of molecules of N₂ = 1 ×10²⁰ molecules

Number of moles of N₂ = ?

Mass in gram of N₂ = ?

Solution:

1 mole of any substance contain 6.022×10²³ molecules

1 ×10²⁰ molecules× 1 mol /6.022×10²³ molecules

0.17×10⁻³ mol

Mass in gram:

Mass = number of moles × molar mass

Mass = 0.17×10⁻³ mol × 28 g/mol

Mass = 4.76×10⁻³  g

Mass = 0.00476 g

22.
An example of amphoteric oxide is
A. Al2O3.
B. CaO.
C. Cuo.
D. SiO2.
E. K20.
Fu** please help​

Answers

Answer:

A (option) .............

Answer:

Al2O3

Explanation:

ZnO,Al2O3,PbO2 are some of the amphoteric oxides

Amphoteric oxides are metal oxides that can react with both acids and bases,so Aluminum oxide can react with both HCl and Sodium hydroxide which is a base

Which is the vector quantity that describes the shortest path between two points?

Answers

The shortest distance taken by the object to reach the destination at a minimum time is called acceleration. Thus value acceleration depends upon the displacement and time.

fountain
21. Calculate the quantity of electricity
in coulombs used when a current of
2.7 ampere is passed through a
solution of silver salt for 25 minutes
20 seconds
A. 87.5
B. 206
C. 1350
D. 4050
E. 4104

Answers

Answer:

4104 Coulombs

Explanation:

charge = time(sec) *current

25*60 =1500+20=1520

2.7A * 1520 sec =4104

4104 C

Convert 76.8 cm to m.

Answers

Answer:

0.768 m

Explanation:

1 cm = 0.01 m

76.8 cm * 0.01 m/ 1 cm

0.768 m

2CuO+2NH3------ 3Cu + 3H2O+ N2. Given that the relative molecular mass of copper oxide is 80, what volume of ammonia is required to completely reduce 120 g of Copper oxide? ( Cu=64, O=16, N=14)​

Answers

Volume of Ammonia(NH₃) = 22.4 L

Further explanation

Given

Reaction

3CuO+2NH₃⇒ 3Cu + 3H₂O+ N₂

In the problem, the CuO coefficient should be 3 not 2

M CuO = 80

mass CuO = 120 g

Required

The volume of NH₃

Solution

mol CuO :

[tex]\tt mol=\dfrac{mass}{M}\\\\mol=\frac{120}{80}\\\\mol=1.5[/tex]

From the equation, mol ratio CuO : NH₃ = 3 : 2, so mol NH₃=

[tex]\tt \dfrac{2}{3}\times 1.5=1~mol[/tex]

Assume at STP(0 °C, 1 atm) ⇒1 mol = 22.4 L, then volume of NH₃=22.4 L

7. Base your answer to the following question on the information below and on your knowledge of biology A student designed an experiment to investigate a claim that athletes would have lower heart rates than nonathletes during exercise. After the students classified themselves as an athlete or a nonathlete, their resting pulses were determined. Then all the students performed the same exercise for four minutes and their heart rates were determined by recording the pulse rate in beats per minute. The students continued to measure their pulse rates for an additional four minutes. The average heart rate per minute for each group was determined. The data were recorded, as shown on the table below Average Heart Rate Response to Exercise (beats per minute) Time (minutes) Athlete Students Nonathlete Students Resting Pulse 68 72 1 76 78 2 82 90 Exercising Period 3 115 95 110 4 130 5 100 125 6 95 120 After Exercise 7 85 100 8 68 95 2.4 To improve the validity of the conclusion reached in this experiment, the students should repeat the experiment A) disregarding any data that don't fit the hypothesis B) with a larger number of athletes and nonathletes C) comparing the heart rates and breathing rates of males and females D) with the athletes doing different exercises than the nonathletes​

Answers

The pulse has to be 130 for I can go through

Qu 4.
How many protons, neutrons, and electrons are present in an atom of gold, Au,
with a mass number of 197?
197 protons, 276 neutrons, 79 electrons
79 protons, 118 neutrons, 79 electrons
Du Do
79 protons, 197 neutrons, 118 electrons
&
118 protons, 72 neutrons, 118 electrons

Answers

Answer:

It's the second one down.

Explanation:

Gold

Mass 197

Number of Protons: 79

Number of Neutrons: 197 - 79 = 118

Number of electrons: = number of protons = 97

Displacement can be added to get the total
a) velocity
b) distance
c) speed
d) acceleration

Answers

im pretty positive it’s velocity i remember learning about this last year in physics sorry i don’t have an explanation but i’m pretty sure it’s velocity

write the metals and nonmetals and metalloids in the first 30 elements​

Answers

Answer: Metals: Li, Be, Na, Mg, Al, K, Ca, Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn

Non-metals: H, He, C, N, O, F, Ne, Si, P, S, Cl, Ar

Metalloid: B

Explanation: The first 30 elements are H, He, Li, Be, B, C, N, O, F, Ne, Na,

Mg, Al, Si, P, S, Cl, Ar, K, Ca, Sc, Ti, V, Mn, Fe, Co, Ni, Cu, Zn

Metallic elements are more electropositive (tending to form ions by donating electrons) with fewer electrons in their outer shell

Non-metallic elements are more electronegative (tending to form ions by accepting electrons) with more electrons in their outer shell

Metalloids are elements somewhere between, but without any specific clear boundary between them and metals/non-metals

group1 and group2 elements, with one or two outer electrons, are all metals: Li, Na, K, Be, Mg, Ca

similarly the transition metals 21-30 are all electropositive and metals.

The noble gases He, Ne, Ar are gases that have completed outer shells and are non-metallic, likewise the halogens F, Cl with 7 outer electrons, and  O and S with 6 are non-metals. N and P (5 outer electrons) are non-metallic as are C and Si (4 outer electrons).

This leaves H, B, Al. H, with its single electron close to the nucleus is a non- metallic gas. Al (3 outer electrons) is metallic, but B, has its 3 electrons close to the nucleus and has the in-between character of a metalloid.

An allotrope of carbon that is structured in a sphere is called:
A. fullerene
B. tetrahedron
C. graphite
D. diamond

Answers

Answer:

fullerene

Explanation:

what is the molar mass of nickel (ll) chloride(NiCl2)

Answers

Answer:

Explanation:

yt

Answer:

129.5994 g/mol

Explanation:

Theresa creates an experiment where she mixes two red-colored substances together in a container and observes the solution slowly changing from red to blue for the next eight minutes. The solution becomes completely blue after eight minutes. What does this represent about the type of change happening in the container?

Answers

Complete Question:

Theresa creates an experiment where she mixes two red-colored substances together in a container and observes the solution slowly changing from red to blue for the next eight minutes. The solution becomes completely blue after eight minutes. What does this represent about the type of change happening in the container?

Group of answer choices

A. A chemical change started immediately and finished at eight minutes.

B. A non-chemical change started immediately and finished at eight minutes.

C. A chemical change occurred at four minutes.

D. A non-chemical change occurred at four minutes.

Answer:

A. A chemical change started immediately and finished at eight minutes.

Explanation:

A chemical reaction can be defined as the chemical process which typically involves the reaction between two or more chemical elements (substances) to form a new compound, through the rearrangement of the ionic or molecular structure of each chemical element.

This ultimately implies that, a chemical reaction is a chemical change that immediately starts when two or more molecules of a chemical element (substance) known as reactants are combined together to form a new product (compound).

In this scenario, Theresa creates an experiment where she mixes two red-colored substances together in a container and observes the solution slowly changing from red to blue for the next eight minutes. The solution becomes completely blue after eight minutes. Thus, what this represent about the type of change happening in the container is that, a chemical change (from red to blue) started immediately and finished at eight minutes.

Which of the following would increase the intensity of the tornado?

a. decrease in wind speed
b. decrease in condensation
c. increased rate of evaporation
d. increase of cold air

Answers

I think the answer would be C. Not totally sure, but hope this helps.

Is the sodium Nitrate solution acidic, basic , neutral? and why ? ​

Answers

Answer: Sodium Nitrate solution is neutral.

Explanation: Sodium nitrate solution has strong bases and strong acids so it would have a neutral pH of 7.

Margarita set up three vials on a hot plate. She poured the same amount of
liquid into each of the vials, and then she turned on the hot plate. Which event
could be a significant source of error in her experiment?

Answers

Answer: Since the vials are filled the same, and are placed on the same hot pad, all the water will evaporate at the same time

Explanation:

The source of error in the experiment  is the vials  being filled the same, and  placed on the same hot pad, all the water evaporating at the same time .

What are errors?

Errors in chemical analysis result when there is a difference between observed value and the true value.If the magnitude of errors is large , it results in decrease in accuracy, reproducibility, and precision.

There are three types of errors:1) random error 2) systematic error 3) human error.The cause of random errors are difficult to quantify while the human errors can be minimized by taking a range of readings to reduce the error.

Errors while measuring boiling point may be human errors while noting down the boiling temperature or instrumental or systematic error if there is a fault in the thermometer.

Learn more about error,here:

https://brainly.com/question/15810279

#SPJ7

Each organ system has specific functions for the body's survival. Which body system is responsible for carrying oxygen from the lungs to the body cells and transporting glucose for energy?
Group of answer choices

Answers

Answer:

Circulatory System

Explanation:

Blood carries oxygen to the rest of the body, as well as glucose.

Other Questions
46.798 divided by 9.086 I can be found in the 4th period on the periodic table.Vanadium (V)Zirconium (Zr)Carbon (C)Beryllium (Be) PLEASE Help me on these questions from the movie osmosis jones9. What causes an increase in nasal secretions? 11. How does the body detect foreign invaders? 13. Explain the defense mechanism of Osmosis Jones. 17. How and where was the antihistamine disposed of? 19. What kind of WBC is Osmosis Jones? 23. What did Osmosis Jones retrieve to save the Father? 24. What is the moral of the story? Graph the inverse of each functionPlease show work will give brainillest The sum of two numbers is 123 and the difference of the two numbers is 47. What are the two numbers? What were some of the causes and effects of the fall of the Byzantine Empire? HELP MEEEE PLEASE if andrew walks 1.8 kilometers on monday night how many cm route is on the map? Type the correct answer in the box.What weather pattern did Indian farmers depend on to bring water for their crops?Indian farmers depended on the__________to bring water for their crops. Your skin is an important organ and has several functions. All of the functions below are performed by the skin EXCEPTA)makes vitamin D.Bprevents-dehydration:C)maintains body temperature.D)works with bones to help you move. Which element has the highest electronegativity? list five symbols in the tragic prelude painting and explain what about them Solve the equation56 (-8)= ? SOMEONE HELP ME PLEASE ILL GIVE BRAINLY Chemical change physical change Claudia necesita comprar ___bonitas. (1 point)1) las blusas2) las sandalias3) las botas4)las gorrasHelp What keeps cells from growing indefinitely? If you can can you answer these two questions or at least one Which choice BEST describes the method of organization used in thispassage?A)The author uses a claim/support structure.B)The author moves from problem to solution.C)The author follows a chronological pattern ofdevelopment.D)The author describes the benefits of video games inorder of importance. another name for a chemical change is a chemical property in science HELP ASAP, ITS TIMEDBacteria and fungi are considered as:Select one:a. omnivore.b. decomposer.c. herbivores.d. carnivore Find two numbers that Multiply to -40 and add to 6