Explanation:
Before melting,Substance are in Solid state.
Which of the following is NOT true of a chemical change?
A. Chemical bonds are broken
B. The identity of a substance has
changed
C. The substance has only
changed form or appearance
D. It can be indicated by the
presence of bubbles or rust
Click here to access the interactive simulation. You will practice balancing chemical equations by playing an interactive game. After accessing the website, select the game box and start with level 1, followed by levels 2 and 3. The goal of these games is to have the same number of atoms on each side of the equation.
In level 1, you balanced the equation N2 + H2 →
NH3. What number did you place in front of ammonia (NH3)?
In level 2, you balanced the equation C + H2O → CH4 +
CO2. What number did you place in front of carbon dioxide (CO2)?
In level 3, you balanced the equation NH3 + O2 → NO2 +
H2O. What number did you place in front of water?
Answer:
In level 1, you balanced the equation N2 + H2 →
✔ 2
NH3. What number did you place in front of ammonia (NH3)?
In level 2, you balanced the equation C + H2O → CH4 +
✔ 1
CO2. What number did you place in front of carbon dioxide (CO2)?
In level 3, you balanced the equation NH3 + O2 → NO2 +
✔ 6
H2O. What number did you place in front of water?
Explanation:
Edge:2020
Answer: 2,1,&6
Explanation: the answer
Which object has the lowest density
beach ball
water
sand
How long will a 25.00 g
sample of americium-241
toke to decay to form a 6.25
g sample of americium-241?
Answer:
Hope it helps.
Explanation:
It decays by beta particle emission into xenon-131. After eight days have passed, half of the atoms of any sample of iodine-131 will have decayed, and the sample will now be 50% iodine-131 and 50% xenon-131
Heavy unstable atoms will continuously emit radiation and will undergo nuclear decay to form stable products. 25 g of americium -241 will take 39 years to decay into its 6.25 g sample.
What is radioactive decay?Heavy unstable nuclei undergo decay when they emit radiations of alpha, beta or gamma particles. After that they will form stable isotopes or other lighter nuclei after emitting these charged particles.
The time an unstable nuclei takes to decay into half of its initial amount is called half life time. The half life time of Americium -241 is 432 years. Thus half life time of 25 g of Am-241 is
= (25 × 432 )/241
= 44.81 years.
The decay constant k can be calculated as follows:
k = 0.693 /half life time
= 0.693 /44.81 yrs
= 0.015.
Now the time taken for the decay process is calculated by the following equation:
t = 1/k log (25/6.25)
= 1/0.015yr-1 log (25/6.25)
= 39 years
Hence, 5 g of americium -241 will take 39 years to decay into its 6.25 g sample.
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ANSWER PLEASE!!
Which one of the following explains why the atom in the diagram
is highly reactive?
option c is correct
number of electron in the outermost shell describe the reactivity if the outermost shell is completely filled its mean the reactivity of element is low and if it is completely filled then the element is highly reactive
What happens when two positively charged particles are close together? A. They repel each other.
B. They cancel each other.
C. They attract each other.
D. They have no effect on each other.
Answer:
A is the ans
Explanation:
they repel each
Decide which element probably forms a compound with oxygen that has a chemical formula most and least similar to the chemical formula of the compound formed by oxygen and cesium.
Answer:
Most similar ----- Lithium
Least similar ---- Nitrogen
Explanation:
Cesium is an element on the periodic with the atomic number 133. It lies in group 1 (i.e., the alkali metals) and period 6 on the periodic table. The oxidation state of group 1 metals is +1. Cesium forms an oxide with oxygen as [tex]Cs_2O[/tex].
The most similar compound to this chemical compound is Lithium because Lithium happens to be in the same group one metal with Cesium and forms the compound [tex]Li_2O[/tex] with the oxygen
The least similar compound nitrogen due to fact that it is an oxide that is covalent in nature and lies between-group 3 -17 to form an [tex]NO_2[/tex] with oxygen.
Describing Diffusion
What happens when molecules diffuse across the cell membrane?
The molecules diffuse until all of them are outside the cell.
The molecules move from areas of low concentration to high concentration.
The molecules move from areas of high concentration to low concentration.
The molecules diffuse until all of them are inside the cell.
Answer:
its the 3rd option.
the molecules move from region of higher concentration to a region of lower concentration.
Explanation:
please do give me brainliest if this helped you.
thank you and have a great day :D
Answer:
The molecules move from areas of high concentration to low concentration
Explanation:
Which describes a property of water that allows plants to transfer it from their roots to their leaves?
O Water exhibits weak adhesion and cohesion, which allows capillary action to occur.
O Water exhibits strong adhesion and cohesion, which allows capillary action to occur.
Water has low surface tension, which prevents capillary action from occurring.
Water has high surface tension, which prevents capillary action from occurring.
Answer:
B water exhibits weak adhesion and cohesion which allows capillary action to occur.
Explanation:
took the test
Water exhibits strong adhesion and cohesion, which allows capillary action to occur.
What property of water allows it to move through a plant?The cohesive properties of water (hydrogen bonding between adjacent water molecules) allow the column of water to be 'pulled' up through the plant as water molecules are evaporating at the surfaces of leaf cells. This process has been termed the Cohesion Theory of Sap Ascent in plants.
What are adhesion and cohesion?Cohesion and adhesion are two water properties that describe how water molecules interact with each other. and how water molecules interact with other things like leaves or even you. Cohesion means that water likes to stick to itself and adhesion means that water likes to stick to other things.
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Which of the following statements is true? a. A technological society has no impact on the environment. b. A technological society has a completely positive impact on the environment. c. A technological society has both a positive and negative impact on the environment d. A technological society has a completely negative impact on the environment. Please select the best answer from the choices provided A B C D
Answer:
The invention of the wheel had an important impact on farming.
Answer:
C
Explanation:
Just took the test
How many valence electrons does aluminum (AI) have available for bonding?
1
2
3
4
Where you would find water on Mars
Answer:
Researchers have found evidence of an existing body of liquid water on Mars.
What they believe to be a lake sits under the planet's south polar ice cap, and is about 20km (12 miles) across.
What are the Oxidation numbers for H2AsO4-
i cant understand your question define briefly
2. What was the primary reason in the 1850's driving the curiosity of atoms?
1905-Einstein
1827-Brown
The primary reason that large numbers of people left Ireland in the 1840s and 1850s was MASS STARVATION.
Great Famine or Great Hunger was a period in Ireland where mass starvation, diseases, and emigration occurred between 1845 to 1852.
The Great Famine was caused by Phytophthora infestans, a disease that infests in potatoes. Though the potato infestation spread throughout Europe, it greatly affected Ireland, where 1/3 of its population was dependent on the potato crop as their primary source of food.
The loss of their primary source of food led to mass starvation, sickness, and eventual death. Others opted to leave Ireland and seek shelter and food in other countries to survive.
Scientists have changed the model of the atom as they
have gathered new evidence. One of the atomic
models is shown below.
What experimental evidence led to the development of
this atomic model from the one before it?
A few of the positive particles aimed at a gold foil
seemed to bounce back.
The colors of light emitted from heated atoms had
very specific energies.
Experiments with water vapor showed that elements
combine in specific proportions.
Cathode rays were bent in the same way whenever
a magnet was brought near them.
Answer:
C)Equations were used to identify regions around the nucleus where electrons would likely be.
Explanation:
edgenuity 2020
Answer:
Equations were used to identify regions around the nucleus where electrons would likely be.....(C).....
Explanation:
hope this helps. the person above me is correct, the comments were looking for a different question
What best describes the temperature at which a solid turns into a liquid
O Melting point
O Boiling point
Electrical conductivity
Thermal conductivity
The subatomic particle that has a mass equal to the neutron but carries a positive charge is the:
1. Nucleus 2. Electron 3. Proton 4. Neutron
o1 o4 o2 o3
Answer: PROTON
Explanation:
a stable subatomic particle that has a positive charge equal in magnitude to a unit of electron charge and a rest mass of 1.67262 × 10 −27 kg, which is 1,836 times the mass of an electron. Protons, together with electrically neutral particles called neutrons, make up all atomic nuclei except for the hydrogen nucleus (which consists of a single proton).
I need help please, I will give you five stars
Answer:
The second choice i think
Explanation:
Hope it helps
Which is more viscous - petrol or diesel?
Answer:
Petrol....follow me and mark me brainliest
Answer The answer to this question is diesel.
Explanation:
Hi there, hope this helps!
mass , volume, and density are all properties of what
Answer: Physical properties
Explanation: Can be measured without changing a substance's chemical identity.
Will a crayon dissolve in water?
Answer:
Yes
Explanation:Like wax crayons but they can dissolve in water.
Answer:
ye bit
Explanation:
Which of the following is true about scarcity?
Answer:
It would be
a) Scarcity affects all societies.
What do hydrologists primarily study?
O A. Stars
O B. Rocks
O c. Water
O D. Weather
An atom with 17 neutrons has a mass number of 33. What is this element?
The table shows four samples of carbon dioxide and the temperature of the water that they were dissolved in. Which of the samples most likely had the lowest solubility? I know the answer is sample one (78) but i can't find the right words to explain my answer.
Answer:
Sample 1 = 78°
Explanation:
As per the question, while testing the solubility of a solution comprising of water and carbon dioxide, sample 1 is likely to have the lowest solubility with the temperature of the water being 78°, the maximum. The reason for this result is that the 'solubility of carbon dioxide in the water' falls with an increase in the temperature due to the increase in kinetic energy which will enhance the motion between the molecules and allow them to escape.' Thus, the water with maximum temperature will have the lowest solubility. Hence, sample 1 is the correct answer.
Which metal would have more luster, zinc (30) or scandium (21)?
Answer:
i say zinc would
Explanation:
what is the chemical name of C9F7
Answer:
Chlorogenic acid.
Explanation:
Answer:
chlorofluorocarbons
Explanation:
To separate a mixture of iron filings and salt, the most efficient method would be
Answer:
Explanation:
Of course you could do the separation chemically. Dissolve the salt up in water, pass thru a filter, wash the iron filings with ethanol, which would encourage the salt to precipitate from solution.
I do hope I helped you! :)
Answer:
by passing a magnet through the mixture
Explanation:
100 Points Will Make Brainliest. Help Me Please.
I said glasses and gloves first time and it was wrong.
Which of the items shown here will protect you from a chemical burn? Select all that apply.
A hand in a rubber glove.
A fire extinguisher.
A pair of glasses with clear shields attached on the sides.
A power source.
If the glasses and glove were wrong then I would chose the fire extinguisher and the power source should be the correct answer.
That's just what I would do though.
Answer:
rubber gloves and glasses
Explanation:
rubber gloves and glasses
Chelsea went ice skating. The ice, her skates, the Zamboni, and the rink building were all examples of solids she encountered. She developed a model of the particles in the ice. Which of statements about the particles present in her model of solid are true?????? Choose the statements that apply.
A. they vibrate in place
B. they slide past each other
C. they are packed very closely together
D.they cause the solid to have a definite volume and definite shape
I think it is d c and a I may be wrong☺️
Answer:
Answers are C, D
Explanation:
Solid particles always stick together no matter what happens unless it is changing into a liquid. If you are talking about vibration for solid particles that only applies to thermal vibratio so not A. They do not slide past each other because they are packed very tightly together. They have a definite shape and volume because they stay together unless facing heat. Hopefully this helps you :)
pls mark brainlest ;)
The statements about the particles present in her model that are true;
C and D
They are packed very closely together ( C ) They cause the solid to have a definite volume and definite shape ( D )Particles of solids are closely packed and this feature distinguishes a solid from other forms of matter ( liquid and gas ). Solids have a definite volume and shape due to their closely packed particles.
Vibration in solids occur when solids are under thermal pressure and from her skating activity, there was no form of thermal pressure therefore solids vibrating in place would not be included in her model.
Hence we can conclude that The statements about the particles present in her model that are true; they are packed very closely together and They cause the solid to have a definite volume and definite shape
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