Formation of small pieces of iron shavings is a physical change whereas burning of pieces of iron shavings is chemical change.
Formation of small pieces of iron shavings is an example of physical change because it can be changed again into nail while on the other hand, burning of pieces of iron shavings on the flame is an example of chemical change because it can't change again into its original shape. Physical change is a change in matter which does not change the chemical properties of the matter whereas chemical change is a change in matter which change the chemical properties of the matter.
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Convert 15,000 seconds into minutes
Answer:
250 minutes
Explanation:
60 seconds = 1 minute
15000 secods = 15000 / 60
1500 secons = 250 minutes
which of the following will show tyndall effect ?
a. salt solution
b. copper sulphate solution
c. starch solution
d. chalk powder in water
Answer:
Starch solution
Explanation:
Colloidal solutions show tyndall effect and starch solution is a colloidal solution.
In a chemical equation, the symbol that means "dissolved in water" is _____. (s) (l) (aq) (g)
[tex]64.000L-4000dL[/tex]
Answer:
4000dl / 10 = 400l
64L - 400L
-336L
a. For a chemistry lab final exam, a high school chemistry student was given a 1-mole sample of CaCl2 and a 1-mole sample of MgCl2 but was not told which sample was which. He was to identify the powders.
He looked up the enthalpies of formation for both of the chemicals and calculated the ΔHreaction for dissolving each powder: CaCl2 (s) Ca 2+ (aq) + 2Cl – (aq), and MgCl2 (s) Mg 2 (aq) + 2Cl – (aq). He then put each powder in a coffee-cup calorimeter and added water.
When sample A dissolved, the temperature increased by 0.74°C. When sample B dissolved, the temperature increased by 0.39°C. Which chemical was A, and which was B? Use the table of enthalpies of formation to help you. Explain your reasoning.
Ca^2+ ion is smaller than Mg^2+ ion hence it has a greater heat of formation or lattice energy.
When a crystal lattice is formed, the energy that is released if the component ions of the compound are brought together from infinity is called the lattice energy. It is the energy released when a crystal lattice is formed from its component ions.
The question lets us know that the heat released by the compounds depends on the energy released upon formation of the compound. Hence, the higher the energy released upon formation, the higher the magnitude of heat released upon dissolution of the compound.
Recall that lattice energy depends on the size of the ions. Thus, the smaller the ions, the higher the lattice energy.
Ca^2+ is smaller than Mg^2+ hence more energy is given off when CaCl2 is formed than when MgCl2 is formed.
As stated above, the greater the lattice energy, the greater the heat released when the lattice dissolves and the higher the rise in temperature.
Putting all these together, Sample A must be CaCl2 while sample B must be MgCl2.
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How do experiments help scientists learn about the world?
A. Experiments explain scientific theories.
B. Experiments prove the scientists' hypotheses.
C. Experiments test the scientists' ideas.
D. Experiments correct old ideas.
Answer:
C. Experiments test the scientists' ideas.
Explanation:
Experiments test the scientists' ideas. Therefore, the correct option is C.
By testing ideas and hypotheses, experiments are an essential part of the scientific method and aid scientists' understanding of the world. Science uses regulated procedures to detect particular phenomena, track results, and collect data. These studies give researchers a chance to investigate cause-and-effect relationships, detect patterns, and draw conclusions based on the data. Scientists can test their ideas, theories, and predictions by systematically adjusting various factors to see whether experimental results confirm or disprove them.
Therefore, the correct option is C.
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what is used in conjunction with a scale balance to weigh dry chemicals
The word "atom" comes from the Greek word
Answer:
1) atomos. 2) uncuttable.
Explanation:
none
Which of the following chemical equations depicts a balanced chemical
equation?
O A. AgNO3 + K2 CrO4- > KNO3 + Ag2Cr04
B. 3AgNO3 + 2K2 CrO4- > 3KNO3 + 2Ag2 CrO4
OC. 2AgNO3 + K2 CrO4- > 2KNO3 + Ag2Cr04
OD. AgNO3 + K2 CrO4- > 2KNO3 + Ag2Cr04
Reset Selection
Answer:
C.
Explanation:
I believe C is the correct answer.
Which of the following units are commonly used in chemistry? A Kelvin b ampere c fluid ounce d kilogram
Explanation:
your answer is Kelvin because it is the SI unit of temperature
50. Carbon mono-oxide can be prepared by heating following substance with Conc. H2SO4. a. Oxalic acid b. Acetic acid c. Ethanoic acid d. All ic 252
A
Carbon monoxide gas can be prepared in lab by heating formic acid or oxalic acid with conc. H2SO4.
Procedure: Small amount of oxalic acid crystal is taken in a round- bottomed flask and all the apparatus are fitted as shown in figure. When conc. H2SO4 is poured in the flask through thistle funnel and heated then a mixture of CO and CO2 gas is formed. The mixture of gas is passed through a bottle containing NaOH solution where the CO2 gas is absorbed by NaOH.
2NaOH + CO2 → Na2CO3 + H2O
The pure CO gas is then collected in a gas jar by downward displacement of water.
Write the valence shell electronic configuration of an element present in the 3rd
period and Group IIIA,
Al= [Ar] 3s^2 3p^1
for the third period the principal quantum number is n=3. the third
URGENT PLS HELP What are derived units?
Answer:
A derived unit is a unit that results from a mathematical combination of SI base units. We have already discussed volume and energy as two examples of derived units.
why hydrogen and oxygen all around us dows not form water
Answer:together doesn't make water
Explanation:
together doesn't make water
6. What type of bond is called covalent bond?
Answer:
ECovalent bond, in chemistry, the interatomic linkage that results from the sharing of an electron pair between two atoms. The binding arises from the electrostatic attraction of their nuclei for the same electrons. ... Silicon, carbon, germanium, and a few other elements form covalently bonded solids.
Please make me Brain liest );
ammonium hydroxide molecular weight?step by step????
Lets find
[tex]\\ \sf\longmapsto NH_4OH[/tex]
[tex]\\ \sf\longmapsto 14u+4(1u)+16u+1u[/tex]
[tex]\\ \sf\longmapsto 14u+4u+17u[/tex]
[tex]\\ \sf\longmapsto 18u+17u[/tex]
[tex]\\ \sf\longmapsto 35u[/tex]
Suppose you had a valuable collection of small diamonds, which you kept safe from the thieves by mixing them with white sugar crystals. You store the mixture in a jar labeled 'sugar'. Now you want to sell the diamonds. Describe how you would separate all the diamonds from the sugar.
Answer:
Pour the sugar/diamond mixture into a container of water and stir until the sugar is dissolved completely. Then strain the mixture and wash the diamonds with water.
Answer:
Stir with a large enough volume of cold water to dissolve all the sugar. Filter to leave the diamonds on the filter paper. Wash on the filter paper with more water to remove any last traces of sugar solution. Allow to dry.
You measure the mass of an unknown piece of metal to be 325 grams. The
volume of the metal is measured to be 16.8 cm3. What is the density of the
piece of metal? What kind of metal is it?
Answer:
The metal is a steel that might be casted.
Explanation:
Using the mesh analysis to solve choleski and gauss jacobi and siedel
Sarah measures out 151 grams of SO2. How many moles is this? Express your answer to three significant figures.
Answer:
[tex]\boxed {\boxed {\sf 2.36 \ mol \ SO_2}}[/tex]
Explanation:
We are asked to convert grams to moles. We will use the molar mass and dimensional analysis to perform this conversion.
1. Molar MassThe molar mass is the mass of 1 mole of a substance. These values are found on the Periodic Table because they are equivalent to the atomic masses, but the units are grams per mole instead.
We are given a mass of sulfur dioxide (SO₂). Look up the molar masses of the individual elements.
Sulfur (S): 32.07 g/mol Oxygen (O): 15.999 g/molNotice that the formula of the compound contains a subscript. The subscript after O means there are 2 moles of oxygen in 1 mole of sulfur dioxide. We must multiply oxygen's molar mass before adding sulfur's.
O₂: 15.999 * 2 = 31.998 g/mol SO₂= 32.07 + 31.998 = 64.068 g/mol2. Convert Grams to Moles
Now we will use dimensional analysis to convert grams to moles. From the molar mass, we know there are 64.068 grams of sulfur dioxide per mole, so we can set up a ratio.
[tex]\frac {64.068 \ g \ SO_2} {1 \ mol \ SO_2}[/tex]
We are converting 151 grams to moles, so we multiply by this value.
[tex]151 \ g \ SO_2 *\frac {64.068 \ g \ SO_2} {1 \ mol \ SO_2}[/tex]
Flip the ratio so the units of grams of sulfur dioxide cancel.
[tex]151 \ g \ SO_2 *\frac {1 \ mol \ SO_2}{64.068 \ g \ SO_2}[/tex]
[tex]151 *\frac {1 \ mol \ SO_2}{64.068 }[/tex]
[tex]\frac {151}{64.068 } \ mol \ SO_2[/tex]
[tex]2.356870825 \ mol \ SO_2[/tex]
3. RoundThe original measurement of grams (151) has 3 significant figures, so our answer must have the same. For the number we calculated, that is the hundredth place. The 6 in the thousandth place tells us to round the 5 in the hundredth up to a 6.
[tex]2.36 \ mol \ SO_2[/tex]
151 grams of sulfur dioxide is approximately 2.36 moles of sulfur dioxide.
A student conducts an experiment to determine how the temperature of water affects the time for sugar to dissolve. In each trial, the
student uses a different amount of water and a different temperature of water.
What is wrong with this experimental design?
The fact that the student used different amount of water (another independent variable) is wrong with the experimental design
WHAT ARE THE COMPONENTS OF AN EXPERIMENT?
An experiment aims at solving a scientific problem or answering a scientific question. An experiment should contain a variable being changed called INDEPENDENT VARIABLE and a variable being measured called DEPENDENT VARIABLE. In an ideal experiment, only one independent variable should be used while every other variable should be kept constant. This is done so as not to affect the result of the experiment.In the experiment conducted by the student in this question, two independent variables were used i.e. the different amount of water and the different temperatures. This is what is wrong about the experimental design.
In a nutshell, the fact that two independent variables were used by the student is what is wrong about the experimental design.Learn more at: https://brainly.com/question/967776
Answer: In an ideal experiment, only one independent variable should be used while every other variable should be kept constant.
cho 3,8g hỗn hợp na2co3 và nahco3 tác dụng với dung dịch hcl.Thoát ra 896 khí ở đktc a/ tính thành phần % theo khối lượng mỗi muối trong hỗn hợp đều.b/ tính thể tích dung dịch hcl 20% biết d= 1,1g trên ml
Answer:
99
Explanation:
it is matter so it and it has.bein 99
PLS HELP WILL GIVE BRAINLIEST
it is a simple chemistry question
i thought F has 9 electrons, so why does this structure show 8 electrons.
Answer:
The IUPAC structure only shows bond pairs and lone pairs. In the flouromethane structure above, there is only one bond pair and three lone pairs of electrons. Therefore there is one electron remaining, but since it doesn't not make up a pair, it is ignored in the structure but theoretically it is present.
[tex].[/tex]
Answer:
therefore there is one electron remaining , but since it doesn't make up a pair . It is ignored in the structure but theoretically it is present .
How many moles of Ba(OH)2 are present in 205 mL of 0.600 M Ba(OH)2?
Answer:
Explanation:
0.180 moles of Ba(OH)2 are present.
Answer:
[tex]\boxed {\boxed {\sf 0.123 \ mol \ Ba(OH)_2}}[/tex]
Explanation:
Molarity is a measure of concentration in moles per liter. It is calculated using the following formula:
[tex]molarity= \frac{moles \ of \ solute}{liters \ of \ solution}[/tex]
The molarity of the solution is 0.600 M Ba(OH)₂. 1 molar (M) is also equal to 1 mole per liter, so the molarity is 0.600 moles of Ba(OH)₂ per liter.
The volume of the solution is 205 milliliters, however, we need to convert the volume to liters. Remember that 1 liter contains 1000 milliliters.
[tex]\frac { 1 \ L}{1000 \ mL}[/tex][tex]205 \ mL * \frac { 1 \ L}{1000 \ mL} = \frac {205}{1000} \ L = 0.205 \ L[/tex]Now we know the molarity and volume, but the moles are still unknown.
molarity = 0.600 mol Ba(OH)₂/ L moles of solute = x liters of solution = 0.205 LSubstitute these values into the formula.
[tex]0.600 \ mol \ Ba(OH)_2 /L = \frac{x}{0.205 \ L}[/tex]
We are solving for x or the moles of solute, so we must isolate the variable. It is being divided by 0.205 liters. The inverse of division is multiplication. Multiply both sides by 0.205 L.
[tex]0.205 \ L *0.600 \ mol \ Ba(OH)_2 /L = \frac{x}{0.205 \ L} * 0.205 \ L[/tex]
[tex]0.205 \ L *0.600 \ mol \ Ba(OH)_2 /L =x[/tex]
The units of liters cancel.
[tex]0.205 *0.600 \ mol \ Ba(OH)_2 =x[/tex]
[tex]0.123 \ mol \ Ba (OH)_2 = x[/tex]
The original measurements had at least 3 significant figures. Our answer currently has 3 sig figs, so we don't need to round.
There are 0.123 moles of barium hydroxide.
50 POINTS!!! PLEASE HELP!!
How did elements with more than 2 protons, such as
the carbon in our cells, form?
A. They formed from hydrogen and helium slamming into each
other in the first few minutes after the big bang.
B. They were formed at the same time as hydrogen and helium right after the big bang.
C. They formed 400 million years after the universe formed in giant fusion reactors known as stars.
D. They are formed when lighter elements are pulled together by gravity to form a planet.
Answer:
D. They are formed when lighter elements are pulled together by gravity to form a planet.
Hope it helps you.The elements with more than 2 protons, such as the carbon in our cells, form when lighter elements are pulled together by gravity to form a planet. The correct option D.
What are elements?
Elements are a substance that has a given number of proton in the nuclei, and they can not be divided into any simpler form in a chemical reaction. Elements are present in the periodic table.
The elements that have 2 protons are formed when the lighter elements collide together in the earth from gravity and constitute a new element.
Thus, the correct option D. They are created when lighter elements are pulled together by gravity to constitute a planet.
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The velocity of an electron that is emitted from a metallic surface by a photon is 3.6E3 km*s^-1. (a) What is the wavelength of the ejected electron? (b) No electrons are emitted from the surface of the metal until the frequency of the radiation reaches 2.50E16 Hz. How much energy is required to remove the electron from the metal surface? (c) What is the wavelength of the radiation that caused photoejection of the electron? (d) What kind of electromagnetic radiation was used?
(a) The wavelength of the electron is 202.25885 nm
(b) The minimum energy required to remove the electron is 1.6565 × 10⁻¹⁷ J
(c) The wavelength of the causing radiation is approximately 8.84 nm
(d) X-ray
The question parameters are;
The given parameters of the electron are;
The velocity of the electron, v = 3.6 × 10³ km/s
(a) de Broglie wavelength is given as follows;
λ = h/(m·v)
Where;
λ = The wavelength of the wave
h = Planck's constant = 6.626 × 10⁻³⁴ J·s
m = The mass of the electron = 9.1 × 10⁻³¹ kg
Therefore, we get;
λ = 6.626 × 10⁻³⁴/(9.1 × 10⁻³¹ × 3.6 × 10⁶) = 202.25885 × 10⁻⁶
The wavelength, λ, of the electron is 202.25885 × 10⁻⁶ m = 202.25885 nm
(b) The energy required to remove the electron from the metal surface is known as the work function, W₀, which is given by the following formula
W₀ = h·f₀
Where;
f₀ = The threshold frequency
Given that the threshold frequency, f₀ = 2.50 × 10¹⁶ Hz, we have;
W₀ = 6.626 × 10⁻³⁴ J·s × 2.50 × 10¹⁶ Hz = 1.6565 × 10⁻¹⁷ J
The energy required to remove the electron from the metal surface, W₀ = 1.6565 × 10⁻¹⁷ J
(c) The wavelength of the radiation that caused the photoejection of the electron is given as follows;
The energy of the incoming photon, E = W₀ + (1/2)·m·v²
Where;
v = The velocity of the electron, and m = The mass of the electron
Therefore;
E = 1.6565 × 10⁻¹⁷ + (1/2) × 9.1 × 10⁻³¹ kg × (3.6 × 10⁶ m/s)² = 2.24618 × 10⁻¹⁷ J
We have;
E = h·f
∴ f = (2.24618 × 10⁻¹⁷ J)/(6.626 × 10⁻³⁴ J·s) = 3.38994869 × 10¹⁶ Hz
The speed of light, c = 299,792,458 m/s
From the equation for the speed of light, we have;
λ = c/f
∴ λ = (299,792,458 m/s)/(3.38994869 × 10¹⁶ Hz) = 8.84356919 nm ≈ 8.84 nm
The wavelength of the radiation that caused photoejection of the electron, λ[tex]_{causing \ radiation}[/tex] ≈ 8.84 nm
(d) The kind of electromagnetic radiation used which has a wavelength of 8.84 nm is the X-Ray which are electromagnetic radiation having wavelengths that extend from 10 picometers to 10 nanometers.
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what happens to rubber when hammered
Answer:
No change
Explanation:
Since rubber are elastic in nature, there's no change in it's state even if it is hammered. So, it will be in it's initial state as it was before.
Is there any Chemical including in BIOGESIC?
Can you tell me if it was included?
Answer:
This combination product contains 2 medications, acetaminophen and an antihistamine. Acetaminophen helps to reduce fever and/or mild to moderate pain (such as headache, backache, aches/pains due to muscle strain, cold, or flu).
Explanation:
it will help you. may be
Answer:
looooser
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Question 4. Thanks !!
Answer:
the shape would be square planar.
Explanation:
From the question, we can see that the electron geometry is octahedral. Removing the two axial bonds to fit the description, and we have a square planar structure.
define briefly about kilogram
Answer:
it's the SI unit of mass (equivalent to
approximately 2.205 lb), first introduced as a unit of mass for the metric system.
What are the standard temperature and pressure conditions enthalpy is usually measured under
Answer:
temperature must be 273 Kelvin (0°C)
pressure must be 1 atm
