A student mixes 20.0gof white KCl crystals with distilled water in a beaker. After the mixture was stirred, no crystals are visible and the solution is clear. After several days, all of the water evaporates and white crystals are found in the beaker. Which of following pieces of experimental evidence would best help the student to confirm that a new compound had not been made and that only a physical change occurred?
a- The solution does not change color after stirring.
b- The KCl crystals are no longer visible after mixing with water.
c- There is a temperature change in the solution during the dissolving process.
d- After the water has evaporated, the white crystals in the beaker have a mass of 20.0g
Answer:d
Explanation: over time water evaporates which leaves you with the white crystals mass
A student in a beaker mixes 20.0 g of white KCl crystals with distilled water; no crystals are visible, and the solution is clear, indicating that the physical change has occurred, which is that after the water has evaporated, the white crystals in the beaker have a mass of 20.0 g; that is option d.
What is the significance of the physical change?The physical change includes the change in the shape and size of the substances but not the chemical change, as in the case of here the crystal, which is left behind after the evaporation of the solution without any change in the chemical composition.
Hence, a student in a beaker mixes 20.0 g of white KCl crystals with distilled water; no crystals are visible, and the solution is clear, indicating that the physical change has occurred, which is that after the water has evaporated, the white crystals in the beaker have a mass of 20.0 g; that is option d.
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the empirical formula for trichloroisocyanuric acid
Answer:
OCNCl
Explanation:
The empirical formula for trichloroisocyanuric acid, the active ingredient in many household bleaches, is OCNCl. The molar mass of this compound is 232.41g/mol.
What type of weathering involves changes in the size or shape of the rock?
A: hydrolysis
B: physical weathering
C: pressure weathering
D: chemical weathering
Answer:
B
Explanation:
The rock is physically weathered down and decreases in size.
What is the chemical composition of dry ice?
Answer:
Dry ice is the solid form of carbon dioxide (CO 2), a molecule consisting of a single carbon atom bonded to two oxygen atoms. Dry ice is colorless, odorless, and non-flammable, and can lower the pH of a solution when dissolved in water, forming carbonic acid (H 2 CO 3).
Explanation: i asked my teacher and this was her response.
What are ocean currents?
Answer:
What are ocean currents?Ocean currents are continuous movements of water in the ocean that follow set paths, kind of like rivers in the ocean.3) The nucleus in a photograph of a cell measures 3 mm across. If the magnification in the photograph is x 500, what is the actual size of the nucleus?
Answer:
1500mm oqkwndbdjdhdndjdd
What happens to the atoms in food once animals eat them?
they are destroyed
they are used to make the animal grow
they are released as waste
Answer:
i think
they are used to male the animal grow
Once the animal eats the food, the atoms in food are used to make the animal grow.
What is an atom?An atom is defined as the smallest unit of matter which forms an element. Every form of matter whether solid,liquid , gas consists of atoms . Each atom has a nucleus which is composed of protons and neutrons and shells in which the electrons revolve.
The protons are positively charged and neutrons are neutral and hence the nucleus is positively charged. The electrons which revolve around the nucleus are negatively charged and hence the atom as a whole is neutral and stable due to presence of oppositely charged particles.
Atoms of the same element are similar as they have number of sub- atomic particles which on combination do not alter the chemical properties of the substances.
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Which chemicals previously used in products such as refrigerants, aerosol sprays, and cleaning products contributed to the depletion of the ozone layer
Answer:chlorofluorocarbons (CFCs) could deplete Earth's atmospheric ozone layer, which blocks the sun's damaging ultraviolet rays. When the scientists reported their findings in 1974, CFCs were widely used as refrigerant gases and as propellants in aerosol sprays
Explanation:
which of the following atom could reside in the same group? Explain your answer
If 65.8 grams of SO3 are produced in the unbalanced reaction below, how many grams of oxygen reacted? SO2(g) + O2(g) —> SO3(g) Show work please.
Answer:
13.13g
Explanation:
65.8÷80.06 =0.821 mol the same
the same amount of moles of Oxygen reacts with
because the ratio is 1 :1-1
let's calculate how much grams for 0.821 of oxygen
oxygen 1 mole is =16 g
well for 0.821=16* 0.821 which is 13.136grams
Under what conditions do you expect hydrogen gas to deviate from ideal gas behavior? Explain your answer.
Please help to complete this
A sample of tin (Cp = 0. 227 J/g•°C) is placed in a freezer. Its temperature decreases from 15. 0°C to â’10. 0°C as it releases 543 J of energy. What is the mass of the sample? Round your answer to three significant figures. G.
Taking into account the definition of calorimetry, the mass of the sample is 478.41 grams.
Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.
Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).
So, the equation that allows to calculate heat exchanges is:
Q = c× m× ΔT
where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.
In this case, you know:
Q= -543 J because the energy is releasesc= 0.227 [tex]\frac{J}{gC}[/tex]m= ?ΔT= Tfinal - Tinitial= 10 C - 15 C= -5 CReplacing:
-543 J= 0.227 [tex]\frac{J}{gC}[/tex]× m× (-5 C)
Solving:
[tex]m=\frac{-543 J}{0.227 \frac{J}{gC}x(-5 C)}[/tex]
m=478.41 grams
In summary, the mass of the sample is 478.41 grams.
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brainly.com/question/11586486?referrer=searchResults brainly.com/question/24724338?referrer=searchResultsTrue or False. When light passes from one medium to another the speed changes.
Answer:
Its actually true
Explanation:
Your Welcome Canada,
OH YEAH!!!!!!
Answer:
The correct answer is "True".
Explanation:
I hope this helps!
Si echamos en un vaso agua y sal el ¿huevo flotaria ? por que
what is the difference between nitrite and nitrate
Answer:
Nitrite:
Formula : NO₂⁻1 nitrogen molecule and two oxygen molecules with an excess electron.Angular shapeNitrate:
Formula: NO₃⁻1 nitrogen molecule and three oxygen molecules with an excess electron.Trigonal planar structure.[tex]\rule[225]{225}{2}[/tex]
Hope this helped!
~AH1807Mass is the amount of matter in an object, but
weight is
A. the size of the matter.
B. the amount of space matter takes up.
C. the shape of the matter.
D. gravity's pull on the matter.
Answer: is equal to the gravitational pull on an object
Explanation:
do Plants and animals create energy the same way?
Answer:
Yes
Step By Step Explanation:
Plants extract energy from food molecules the same way animals do — by cellular respiration.
Most, if not all plants are producers, and they make their own food using sunlight and raw materials, through a process called "photosynthesis". ... Plants get their energy in form of starch whereas animals get it in form of glycogen. Animals get their energy from the food they eat. Animals depend on other living things for food. Some animals eat plants while others eat other animals. This passing of energy from the sun to plants to animals to other animals is called a food chain.
Animals obtain energy from the food they consume, using that energy to maintain body temperature and perform other metabolic functions. Glucose, found in the food animals eat, is broken down during the process of cellular respiration into an energy source called ATP.
Hopes This Helps
The last layer in layered design is _____________. Object Process None of the options Atoms Sub process
The last layer in the layered design is system layer so none of the above is the correct option.
Robotic Process Automation is a software technology that make use of some programs of computer to copy or mimic the behaviors of human when it has access with them. They been use effectively and ensure the work is perfectly done.
There are layers in the Robotic process automation but the last layer is System layer.
They can handle high volume of tasks.
The lowermost layer is associated with individual screen interactions. The lowermost layer in the layered design of Robotic process automation is the component layer or system layer . The Robotic Process Automation and this form technology is in robots creation.
Therefore, The last layer in layered design Is System layer so none of the above is the correct option.
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Which of the following is unlikely to form a compound?
a. S
b. H
c. K
d. Ar
d. Si
Answer:
I think the answer is Ar, k or just k. Can you pick two answers?
Explanation:
I hope this helps.
P.S. you put two d's
how much heat is released when 32g of water cools from 46°C and freezes
The amount of heat released when 32g of water cools from 46°C and freezes is 6182.4 J
Heat: This is a form of energy that brings about the sensation of warmth. The S.I unit of heat is Joules (J)
⇒ Formula:
Q = cm(t₂-t₁).................. Equation 1⇒ Where:
Q = amount of heat releasedc = specific heat capacity of waterm = mass of watert₁ = Initial temperaturet₂ = Final temperatureFrom the question,
⇒ Given:
m = 32 g = 0.032 kgt₁ = 46 °Ct₂ = 0 °C (Freezing point)c = constant = 4200 J/kg.°C⇒ Substitute these values into equation 1
Q = 0.032(4200)(0-46)Q = -6182.4 JNote: The negative sign tells that heat is released and as such can be ignored.
Hence, The amount of heat released is 6182.4 J
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WILL GIVE BRAINLIEST
Which model provides more information-a chemical formula or a sketch of the molecule
like in the structural formula? Explain your reasoning.
Answer:
Explanation
:Both b/c a chemical formula tells you how many and a sketch formula shows how they are bonded together.
Molecular formulas show how many atoms of each element one molecule of a compound contains. Note: Ionic compounds are generally crystalline solids with high melting points. Other compounds, however, have very different properties.
Fluorine-18 undergoes positron emission as shown:
18 F + 4x +48
Enter the appropriate values for A and Z and the chemical
symbol for X
A:
Z:
83
1
X:
Answer:Answer:
40-18 fl =>40-cl+cl+0-1e sorry if im rong
Explanation:
When [tex]^1^8F[/tex] undergoes positron emission, the product nucleus is, [tex]^1^8O[/tex].
What is a positron emission?In positron emission, also called positive beta decay (β+ decay), a proton in the parent nucleus decays into a neutron that remains in the daughter nucleus, and the nucleus emits a neutrino and a positron, which is a positive particle like an ordinary electron in mass but of opposite charge.
When a proton is converted into a neutron then the positron emission takes place as follows.
[tex]^1_1p\;\rightarrow\;^1_0n\;+\;^0_+1e[/tex]
A positron is represented by the symbol. Therefore, when a positron emission occurs then the resultant nuclei atomic number decreases by a unit mass.
The general equation representing positron emission is as follows.
[tex]^M_ZA\;\rightarrow\;^M_Z_-_1 B\;+\;^0_+1e[/tex]
Hence, fluorine-18 decays by positron emission as follows.
[tex]^1^8_9F\;\rightarrow\;^1^8_8n\;+\;^0_+1e[/tex]
Therefore, when [tex]^1^8F[/tex] undergoes positron emission, the product nucleus is, [tex]^1^8O[/tex].
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Why does Alex’s equation better represent the reaction?
Answer : it has been tested
Explanation:
i took the test
Jacinta wrote the following passage about chemical changes.
A chemical change is a change that results in one or more new substances with different properties. When a chemical change occurs, the new substance can give off an odor, such as rotting fruit or cookies baking in the oven. Chemical changes can cause color changes, such as iron rusting and turning a reddish-brown color. When wood is burned or ingredients are mixed for baking a cake, a new substance is made.
Choose the best statement that Jacinta can add to her passage.
Chemical changes, such as rotting fruit and burning wood, are affected by temperature. More heat and energy causes a faster chemical change.
Wood burning and fruit rotting creates new substances through a chemical change that is affected by sound energy.
Rotting fruit and burning wood is a chemical change that occurs because there is a decrease in temperature. Less heat causes a faster chemical change.
When a chemical change occurs, the new substance that is created has properties similar to the original substance.
According to the unbalanced equation above if 8.542 moles of oxygen gas reacts with an excess amount of hydrogen gas, how many grams of water is produced
Answer: 153.8865g?
Explanation:
why does fluorine have the highest electronegativity
Answer:
- Fluorine has 5 Electrons in its 2P shell
- Fluorine is so close to ideal Electron Configuration, the Electrons are held very tightly to the Nucleus.
Explanation:
Hopefully this was helpful!
What is formed if two or more atoms join together?
A. Compound
B. Electronegativity
C. Nucleus
D. Element
HELP
Answer:
compound
Explanation:
compound = A substance consisting of atoms or ions of two or more different elements in definite proportions joined by chemical bonds into a molecule.
which statement describes how vapor pressure occurs? (1 point)
a) Some molecules of a substance have high enough kinetic energy to vaporize. These molecules exert
pressure on the substance.
b) Some molecules of a substance have low enough kinetic energy to melt. These molecules exert pressure on the substance
c) Some molecules of a substance have low enough kinetic energy to vaporize. These molecules exert
pressure on the substance.
d) Some molecules of a substance have high enough kinetic energy to melt. These molecules exert pressure on the substance
Some molecules in a substance have a high kinetic energy hence they are able to convert into vapor. These molecules exert pressure on the liquid surface.
We know that the molecules that compose matter are in constant random motion. The kinetic energy of all the molecules in the liquid are not the same. The molecules at the surface of the liquid posses more kinetic energy than the molecules below.
Some molecules of a substance have high enough kinetic energy to vaporize. These molecules exert pressure on the substance.
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Answer:
Some molecules of a substance have high enough kinetic energy to vaporize. These molecules exert pressure on the substance.
Explanation:
which of the following molecular compounds does NOT need the usage of prefix for the first element
SO2
S2O3
N2S
N2S3
Answer:
SO2
Explanation:
that's my answer
Sana mKatolong
