formation of a solid, formation of a gas, and a color change can also occur during some physical changes. give examples of physical changes that could produce these clues. what evidence suggests that the changes you observed in test tubes 1-3 were, in fact, chemical changes

Answers

Answer 1

Answer:

Examples of these physical changes are melting ice-cream, or boiling water as well as freezing it. Adding dye to water is also a physical change since the chemical compounds remain the same, it is only the physical appearance that changes.

Possible reasons for chemical changes are the formation of a precipitate (solid), or formation of gas (bubbling) as well as release of heat or light or release of odor.


Related Questions

how many grams of kclo3 are needed to make 30.0 grams of kcl

Answers

The mass of  potassium chlorate, KClO₃ needed to produce 30 grams of potassium chloride, KCl is 49.33 grams

Balanced equation

2KClO₃ —> 2KCl + 3O₂

Molar mass of KClO₃ = 39 + 35.5 + (16×3) = 122.5 g/mol

Mass of KClO₃ from the balanced equation = 2 × 122.5 = 245 g

Molar mass of Kcl= 39 + 35.5 = 74.5 g/mol

Mass of KCl from the balanced equation = 2 × 74.5 = 149 g

SUMMARY

From the balanced equation above,

149 g of KCl were obtained from 245 g of KClO₃

How to determine the mass of KClO₃ needed

From the balanced equation above,

149 g of KCl were obtained from 245 g of KClO₃

Therefore,

30 g of KCl will be obtained from = (30 × 245) / 149 = 49.33 g of KClO₃

Thus, 49.33 g of KClO₃ are needed for the reaction

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The addition of a catalyst to a system at equilibrium will increase the rate of:.

Answers

Answer:

forward and reverse reaction rates

Explanation:

meaning the equilibrium is reached faster. So if the reaction is already at equilibrium there will be no effect on a concentration-time or moles-time graph.

Which element is likely to have a high thermal conductivity? antimony carbon chlorine sodium

Answers

The element which is likely to have a high thermal conductivity among given options is sodium.

What is thermal conductivity?

Thermal conductivity of any substance is define as the capability of the substance to carry heat or transfer of heat.

As we know that metals are the good conductors of heat and non-metals are bad conductors, so we exclude carbon, antimony and chlorine atom from this group as they are non-metals. And sodium atom has the thermal capability.

Hence option (4) is correct.

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Answer: Option (4) is correct

Explanation:

Giving brainiest and 100 points! <3

Answers

A. Cold front

The warm front symbol would be red and have circles instead of triangles.

The occluded front symbol would be purple with both, a triangle and a circle.

The stationary Front symbol is a mixture of both symbols from cold front and warm front.

hope that helps!!

give the names of the 5 types of chemical reactions you are responsible for
remembering, and also give the letter model(A + C → D etc.)

Answers

Answer:

What are 5 types of chemical reactions?

1. Combination (Synthesis) reaction. A + B → AB.

2. Decomposition reaction. AB → A + B.

3. Displacement reaction. A + BC → AB + C.

4. Double displacement reaction. AB + CD → AD + BC.

5. Combustion reaction. CH4 +2O2 → CO2 + 2H2O.

Explanation:

Burning fossil fuels creates the ___________ gas carbon dioxide which increases global temperatures.

Question 4 options:

greenhouse


fossil


inert


poisonous

Answers

Greenhouse gas is your answer it is causing the greenhouse effect of trapping heat in the earth

Answer:

green house gas

Explanation:

How many moles of Na are needed to
produce 15 moles of NaCl in the reaction
2Na + Cl2 = 2NaCl?
A conversion involving moles of one
substance to moles of another
substance.

Answers

Answer:

15 moles

Explanation:

15 moles of NaCl will be obtained from 15 moles of Na.

A lot of energy is not stored in biomass, but is used for biological processes instead. Which process removes waste from the body? Give the scientific term.​

Answers

We can confirm that the energy is being used for a biological process to remove waste known as excretion.

What is excretion?

In biology, excretion is a metabolic process in which organisms discard waste and other by-products of metabolism. This process is essential for organisms to maintain homeostasis.

Therefore, we can confirm that energy is being used for a biological process to remove waste known as excretion.

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Which effect can you observe when the starting K2Cr2O7is diluted? Does the position (lambda) of the maximal absorption peaks change? Describe your observations. ​

Answers

After the dillution of the solution, the wavelength of maximum absorption is decreased.

What is the wavelength of maximum absorption?

The wavelength of maximum absorption is the wavelength at which the solution absorbs the maximum amount of light. It is usually shown as a hump in the spectrum.

When the starting concentration of the  K2Cr2O7 is diluted, the wavelength of maxium absorption decreases.

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Which step accurately describes how to measure the final burette volume? Locate the bottom of the meniscus and record volume to the nearest 0. 01 mL. Locate the bottom of the meniscus and record volume to the nearest 0. 1 mL. Locate the top of the meniscus and record volume to the nearest 0. 01 mL. Locate the top of the meniscus and record volume to the nearest 0. 1 mL.

Answers

Burette is the lab equipment used to estimate the volume of liquid during titration. The volume is measured by the bottom meniscus to the nearest 0.01 mL.

What is a burette?

Burette is an instrument used in quantitative analysis like the volume of the sample in the titration methods and is made of a glass tube.

In the volumetric analysis, the final volume of the liquid is measured by locating the lower meniscus and is taken approximately near 0.01 ml as the burettes have markings of 0.1 mL.

Therefore, option a. locate the bottom meniscus and mark nearest to 0.01 mL.

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Thermohaline circulation _______. a. supplies heat to polar regions b. causes salt lake formation c. causes oxbow lake formation d. is unaffected by heat fluctuations Please select the best answer from the choices provided A B C

Answers

Thermohaline circulation that occur in the ocean part that flows across sea surface help to supply heat to polar regions.

What is Thermohaline circulation?

The thermohaline circulation refer to a section and region of the ocean circulation which is majorly driven by heat gradient and freshwater that flows across the sea surface and also from the mixture of heat and salt that occur at the inside part of the ocean.

Therefore, Thermohaline circulation help to supply heat to polar regions.

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Zinc reacts with iron (iii) chloride yielding zinc chloride plus iron

Answers

Answer:

I don't see a specific question, so I'll make a few comments and hope that answers the reason for the post.

Explanation:

Zinc(Zn) does react with iron chloride, since zinc is a more reactive metal than the iron.

When Zn is introduced to an iron (III) chloride solution, the Zn disoplaces the Fe atom in a displacement reaction.

The chemical equation of the reaction:

Zn + Fe(III)Cl3 → ZnCl3 + Fe

Energy is often realeased in this type of reaction, since the resulting chemical products have a lower energy that the reactants.

There are several metals more reactive than iron.  One of the more interesting examples of a highly exothermic reaction with iron chloride (rust) is the reaction of aluminum with iron chloride.  `This is highly exothermic and is labelled a thermite reaction.  It provides a spectacular flame that is not enough to weld railroad tracks together.

what mass TiO2 needs to be dissolved in water to make 0.45 mL of a 0.700 M TiO2 solution

Answers

Volume=0.45mL=0.00045LMolarity=0.7M

No of moles:-

[tex]\\ \tt\Rrightarrow Molarity (Volume)[/tex]

[tex]\\ \tt\Rrightarrow 0.00045(0.7)[/tex]

[tex]\\ \tt\Rrightarrow 0.000315mol[/tex]

Molar mass of TiO_2=79.866g/mol

Mass:-

0.000315(79.866)=0.025157779g

The ionization constant for acetic acid is 1.8 x 10-5; that for hydrocyanic acid is 4 x 10-10. in 0.1 m solutions of sodium acetate and sodium cyanide, it is true that

Answers

For the ionization constant for acetic acid is 1.8 x 10-5; that for hydrocyanic acid is 4 x 10-10, The solution is basic due to the generation of OH– ions.

What is an Ionization constant?

ionization constant is simply defined as a constant that relies on the equilibrium that exists b/w ions and molecules of solution.

Generally, the equation for the Chemical reaction  is mathematically given as

CH3C.O .O + H2_O ----> CH3COOH + O.H

Therefore

the anion C...N–  receives H+ ion from water as it goes through hydrolysis.

Hence

xN– + H2..O ----><---- HxN + O..H–

In conclusion, The solution is basic due to the generation of OH– ions.

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32. 2 g of ethyl alcohol is dissolved in water to make a 0. 50 L

solution. What is the molarity of the solution?

Answers

Answer:

Well, by definition,

molarity = moles of solute

               volume of solution

Explanation:

Now the moles of solute are a constant. The volume of solution MAY change substantially with increasing or decreasing temperature. In some calculations molality is used in preference, which is defined by the quotien

Hope this helps!

How did supporter of the Constitution convince opponents to approve it?

Answers

Add amendments specifically protecting individual liberties

What type of material does not allow electrons to flow easily?

Answers

neutral particles since they do not posses any charge

What factors might affect the amount of energy needed for
evaporation to occur and account for any differences between the temperatures
you observed?

Answers

6 important factors that affect evaporation are : 1. Wind assists evaporation; for example in clothes dry faster under a fan. 2. Heat assists evaporation; for example, in summer clothes dry faster than in winter.

Now have a free meme

An electric motor works by converting electrical energy to mechanical energy in order to create motion.
For example,Force is generated within the motor through the interaction between a magnetic field and winding alternating (AC) or direct (DC) current.
This works because…

Answers

An electric motor works by converting electrical energy to mechanical energy in order to create motion.

For example,Force is generated within the motor through the interaction between a magnetic field and winding alternating (AC) or direct (DC) current.

This works because…

Answer : When an electric current flows through the wire in the electromagnet, a magnetic field is produced in the coil.

[tex]\:\mathsf{Hope\:this\:helps\:you!}[/tex]

Answer:

when an electric current flows through the wire in the electromagnet , a magnetic field is produced in the coil .

Explanation:

Hope it's helpful for you .........

6.
The temperature of a 250.0 g ball of iron increases from 19 C to 32 C. How much heat
did the iron ball gain?
The temperature of a 250.0 g ball of iron increases from 19 C to 32 C. How much heat
did the iron ball gain?

Answers

Q = mc∆T.

the specific heat capacity of iron is 0.450. 250 × 0.450 × (32-19) = 1462.5J

What is the energy required to remove the electron from a hydrogen atom in the n = 11 state?

Answers

Based on the data given, the energy required to remove an electron from a hydrogen atom in the n = 11 state is -0.112 eV

What is ionization energy?

Ionization energy is the energy requiredto remove an electron from a neutral atom or a cation in its gaseous state.

To calculate the energy required to remove the electron from a hydrogen atom in the n = 11 state, the formula below is used:

[tex]E_n = \frac{E_0 × Z^{2}}{n^{2}}[/tex]

where

[tex]E_0 \: is \: ground \: state \: energy \: of \: hydrogen \: atom \: = -13.6 eV \\ [/tex]

Z = 1n = 11

substituting the values:

[tex]E_n = \frac{ - 13.6 × 1^{2}}{11^{2}} \: = - 0.112 \: eV[/tex]

Therefore, the energy required to remove an electron from a hydrogen atom in the n = 11 state is -0.112 eV

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What are some consequences of solar flares in the ocean?

Answers

Answer:

they include pretty aurora as well as hazards

Constance has an apple that weighs 85,000 milligrams and a peach that weighs 0.15 kilograms. which fruit has the greater mass? choose the words and numbers to complete the statements. convert the masses of both fruits to the same unit. 85,000 milligrams is the same as choose... grams. 0.15 kilograms is the same as choose... grams. the choose... has the greater mass.

Answers

The fruit which has the greater mass is peach i.e. 150 grams.

What is mass?

Mass is a quantity which is used to define that what amount of substance will occupy any space or present in the given object.

We have given,

Weight of apples = 85,000 mg

Weight of peach = 0.15 kg

To compare the quantity first we have to convert both of these units in the same unit, and we know that:

In 1 kilogram = 1000 grams

And in 1 grams = 1000 milligrams

So, we convert both the units into grams as:

85,000 mg =  85,000 / 1000 = 85 grams

0.15 kg = 150 grams

So, the mass of peach is high.

Hence, peach has the greater mass.

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Answer:

Constance has an apple that weighs 85,000 milligrams and a peach that weighs 0.15 kilograms. Which fruit has the greater mass? Choose the words and numbers to complete the statements.

Convert the masses of both fruits to the same unit.

85,000 milligrams is the same as  

85

 grams.

0.15 kilograms is the same as  

150

 grams.

The  

peach

 has the greater mass.tion:

what is a water cycle​

Answers

Answer:

the cycle of water and how it evaporates with energy from the sun and the droplets are stored in clouds which is condensation and when it rains or snows those are forms of precipitation

Explanation:

Answer:

it shows the continuous movement of water within the earth and atmosphere

The periodic table is arranged in order by which classification?.

Answers

Answer:

Atomic weight and valence electrons

Explanation:

These variables allow Mendeleev to place each element in a certain row and column. The table comprises 7 rows and 18 columns.

which diver will experience more pressure: A scuba diver at 10 meters or one at 100 meters below at the surface of the water

Answers

Answer:

The one 100 meters below the surface of the water.

Explanation:

As you go deeper into a body of water, there is more water above, and therefore a greater weight pushing you down.

Write some of the chemical and physical properties and uses of each natural resource shown in the photos below.

Answers

(a) Granite is the most common igneous rock found on Earth's surface and is used to make many objects that they encounter in their day to day life. It is used to make countertops, floor tiles, paving stone, curbing, stair treads, building veneer, and cemetery monuments

(b) It doesn't have any color and is a tasteless gas. It is free of any kind of toxic, there is no smoke on burning and it has high calorific value. The gas is odorless. However, a chemical called mercaptan is added to it in small amounts to give it distinctive smell of eggs. The commercial sector uses natural gas to heat buildings and water, to operate refrigeration and cooling equipment, to cook, to dry clothes, and to provide outdoor lighting. Some consumers in the commercial sector also use natural gas as a fuel in combined heat and power systems.

In an experiment using a calorimeter, the following data was obtained:

Mass of calorimeter + water .............150g

Mass of calorimeter ……………………...100g

Final temperature of water …………… 55oC

Initial temperature of water …………. 25oC

What is the total number of Joules absorbed by the water?

Answers

Based on the data provided from the experiment using the calorimeter, the heat absorbed by water is 188.1 Joules

What is a calorimeter?

A calorimeter is an equipment used in the laboratory to enthalpy change of a reaction.

A calorimeter is insulated to ensure no heat losses or gain from the surroundings.

To determine the Joules of heat absorbed by water, the formula below is used:

Heat absorbed = mass × specific heat capacity × temperature difference

Specific heat capacity of water = 4.18 J/g.°C

Heat absorbed by water = 15 × 4.18 × (55 - 25)

Heat absorbed by water = 188.1 Joules

Therefore, the heat absorbed by water is 188.1 Joules.

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CH4 + 2 02 > CO2 + 2 H2O
A scientist wants to completely burn 25 L of methane.
How many molecules of oxygen will the scientist need to
complete this experiment?

Answers

Answer:

mf i was trying to

find out the same thing

Explanation:

compound has a percent composition of 38.7% carbon, 9.76% hydrogen, 51.5% oxygen.
Laboratory data shows that the compound's molar mass is 62.0 g/mol. What is the
molecular formula of the compound?

Answers

The molecular formula for a compound with a percent composition of 38.7% C, 9.76% H, 51.5% O, and a molar mass of 62.0 g/mol is C₂H₆O₂.

What is a molecular formula?

A molecular formula is a chemical formula indicating the kinds and number of atoms of each kind in a molecule of a compound.

To determine the molecular formula, we need to follow a series of steps.

Step 1. Divide the percentage of each element by its molar mass.

C: 38.7/12.01 = 3.22

H: 9.76/1.01 = 9.66

O: 51.5/16.00 = 3.22

Step 2. Divide all the numbers by the smallest one, i.e. 3.22.

C: 3.22/3.22 = 1

H: 9.76/3.22 = 3

O: 3.22/3.22 = 1

The empirical formula is CH₃O and its molar mass is 31.04 g/mol.

Step 3. Determine the molecular formula.

First, we will calculate how many times the empirical formula is contained in the molecular formula by dividing their molar masses.

n = (62.0 g/mol) / (31.04 g/mol) = 2

The molecular formula is 2 times the empirical formula, that is, C₂H₆O₂.

The molecular formula for a compound with a percent composition of 38.7% C, 9.76% H, 51.5% O, and a molar mass of 62.0 g/mol is C₂H₆O₂.

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