Dora rolled a marble down a ramp and recorded the potential energy and kinetic energy of the marble at different positions on the ramp, as shown in the table.



Marble experiment
Height of
Marble from Ground (meters) Potential Energy of
Marble (Joules) Kinetic Energy of
Marble (Joules) Total Energy of
Marble (Joules)
Trial 1 1 2 4 6
Trial 2 2 4 2 6

Which is the constant variable in this experiment?
Mass of marble
Kinetic energy of marble
Potential energy of marble
Height of marble from ground

Answer:

Answer:

15.9994 g/mol

412.056524g is present in 2.3×10^24atoms of Ag

Answer: 16.21

Explanation:

A student measures the length of two pieces of paper as 8.21 in and 8.0 in. the total length is 16.21 with 4 significant figures.

The significant figures or digits are the form of scientific methd which represent the digit from zero to nine and use when the value is uncertain where starting zeros are not significant and decimal is also not a significant figure.

In the given value the total is 16.21 with 4 significant figures with it has 4 significant digits and the decimal with it is not significant after adding from which the respective value is here.

Therefore,  with 4 significant figures where the student measures the length of two pieces of paper as 8.21 in and 8.0 in. the total length is 16.21.

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Answer:

1. λ = 806nm

2. E = 2.6504 × 10^-28J

3. a) f = 1.167 × 10^15 Hz

b) E = 7.73 × 10^-19J

Explanation:

1) The wavelength denoted by λ can be calculated using the formula:

λ = v / f

Where;

v = speed of light (3×10^8m/s)

f = frequency of light (Hz)

λ = 3 × 10^8/3.72 x 1014

λ = 0.80645 × 10^(8-14)

λ = 0.80645 × 10^-6

λ = 8.06 × 10^-7m

λ = 806nm

2) The energy (J) of a photon is calculated thus;

E = hf

Where;

h = Planck's constant (6.626 × 10^-34J/s)

f = frequency (4.00x10^5/s)

E = 6.626 × 10^-34 × 4.00x10^5

E = 26.504 × 10^(-34+5)

E = 26.504 × 10^-29

E = 2.6504 × 10^-28J

3. λ = v / f

2.57x10^-7 = 3 × 10^8 ÷ f

f = 3 × 10^8/2.57x10^-7

f = 1.167 × 10^(8+7)

f = 1.167 × 10^15 Hz

b) E = hf

E = 6.626 × 10^-34 × 1.167 × 10^15

E = 7.7325 × 10^(-34+15)

E = 7.73 × 10^-19J

Answer:

see the pic for the answer

7.91 grams of methane gas occupy a volume of 11.2 liters at STP.

What is STP?

Standard temperature and pressure, abbreviated STP, refers to nominal conditions in the atmosphere at sea level.

First, we need to calculate the number of moles:

STP is 0 °C and 1 bar.

One mole of a gas at STP has a volume of 22.71 L .

Moles of CH₄ = 11.2 L × ([tex]\frac{1 mol}{22.71 L}[/tex])

Moles of CH₄ = 0.4932 mol

Now we will calculate the mass of CH₄

Moles = [tex]\frac{mass}{molar \;mass}\\[/tex]

Mass of CH₄ = 0.4932 × 16.03

Mass of CH₄ = 7.91 g

Hence, 7.91 grams of methane gas occupy a volume of 11.2 liters at STP.

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Answer:

Nitrous oxide, commonly known as laughing gas or nitrous, is a chemical compound, an oxide of nitrogen with the formula N ₂O. At room temperature, it is a colourless non-flammable gas, with a slight metallic scent and taste. At elevated temperatures, nitrous oxide is a powerful oxidiser similar to molecular oxygen.

Explanation:

Answer:

2-5

Explanation:

I just did it.

The oxidation numbers of the atoms in this reaction are 0 for Mg(s) and H in H₂, -1 for Cl in HCl, +1 for H in HCl and +2 for Mg in MgCl₂

An oxidation number is a number assigned to atoms in molecules to show the general distribution of the electrons.

Oxidation state or number helps us describe the transfer of electrons.

The oxidation number/state is also used to determine the changes that occur in redox reactions.

Overall, the oxidation number of an atom in a molecule is the charge that the atom would have if all polar covalent and ionic bonds resulted in a complete transfer of electrons from the less electronegative atom to the more electronegative one.

Therefore, The oxidation numbers of the atoms in this reaction are 0 for Mg(s) and H in H₂, -1 for Cl in HCl, +1 for H in HCl and +2 for Mg in MgCl₂

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Explanation:

A stethoscope is used to listen to sounds that the heart , lungs , blood flow , intestines make.

Answer:

Option B

Explanation:

In order to find the answer to this question you need to move the decimal point as many times as the exponent, positive exponent to the right and negative exponent to the left. In this case we have all positive exponents meaning we move all of them to the right but they all equal the same thing. The most logical answer to this question is option B "10.07×10^4" because the equation is balanced.

Hope this helps.

Answer:

A

Explanation:

it has non polar molecule, because it has the equal sharing of electrons, so equal repulsion from all sides. atoms are equally represented.

Answer:

Trigonal planar, non-polar

Explanation:

Answer:

(a) 133.33nm

(b) 600nm

(c) 7,600nm

Explanation:

The concentration of Y can be determined by using the formula:

[tex]Y = \dfrac{[L]}{k_d+[L]}[/tex]

where;

[L] = concentration of the binding ligand.

kd = 400 nm

Thus:

When Y = 0.25; we get :

[tex]0.25 = \dfrac{[L]}{400+[L]}[/tex]

0.25 (400 + [L]) = [L]

100 + 0.25[L] = [L]

100 = [L] - 0.25 [L]

100 = 0.75 [L]

[L] = 100/0.75

[L] = 133.33 nm

At, Y = 0.6

[tex]0.6 = \dfrac{[L]}{400+[L]}[/tex]

0.6 (400 + [L]) = [L]

240 + 0.6[L] = [L]

240 = [L] - 0.6 [L]

240 = 0.4 [L]

[L] = 240/0.4

[L] = 600 nm

At, Y = 0.95

[tex]0.95 = \dfrac{[L]}{400+[L]}[/tex]

0.95 (400 + [L]) = [L]

380 + 0.95[L] = [L]

380 = [L] - 0.95 [L]

380 = 0.05 [L]

[L] = 380/0.05

[L] = 7600 nm

Answer:

Explanation:

Al(OH)₃

Total molecular weight = 27 + 3 x ( 16+1)

= 78

Al = 27

% of Al = 27 x 100 / 78 = 34.61%

O = 48

% of O = 48 x 100 / 78 = 61.55 %

H = 3

% of H = 3 x 100 / 78

= 3.84%

Al = 34.61%.

O = 61.55%.

H = 3.84%.

Answer:

[tex]\% Fe=11.4\%[/tex]

Explanation:

Hello!

In this case, for the described chemical reaction, we find it is:

[tex]8H^+(aq)+5Fe^{2+}(aq)+MnO_4^-(aq)\rightarrow 5Fe^{3+}(aq)+Mn^{2+}(aq)+4H_2O(l)[/tex]

Because it says that the iron is dissolved in a strong acid which provides addition hydrogen ions to the reaction media. Thus, for the questions attached on the figure we find:

- This a REDOX reaction because we see iron is being oxidized from 2+ to 3+ and manganese reduced from +7 to +2.

- Since it is a redox reaction and the oxidized species is that undergoing an oxidation number increase, we evidence iron goes from +2 to +3, which means iron is the oxidized species.

- In this case, for the used 59.2 mL (0.0592 L) of the 0.2000 M solution of potassium permanganate, we can compute the consumed grams of iron via stoichiometry including the 5:1 mole ratio between them in the chemical reaction:

[tex]m_{Fe^{2+}}=0.0592L*0.2000\frac{molMnO_4^-}{L}*\frac{5molFe^{2+}}{1molMnO_4^-} *\frac{55.85gFe^{2+}}{1molFe^{2+}} \\\\m_{Fe^{2+}}=3.31gFe^{2+}[/tex]

It means that the percent of iron in that sample is:

[tex]\% Fe=\frac{3.31g}{29.00g} *100\%\\\\\% Fe=11.4\%[/tex]

Best regards.

a. P=0.971 atm=737.6 mmHg

b. n=2.88 x 10⁻³

Dalton's law of partial pressures states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the component gases

[tex]\tt P_T=P_1+P_2+..P_n[/tex]

A. vapor pressure of water at 22.5 = 20.4 mmHg

Pt=P H₂ + P H₂O

758 = P H₂ + 20.4

P H₂=737.6 mmHg=0.971 atm

B.Ideal gas Law = PV=nRT

P = 0.971 atm

V = 72 ml = 0.072 L

R = 0.082 L/atm mol

T = 22.5 + 273.15 =295.65

[tex]\tt n=\dfrac{0.971\times 0.072}{0.082\times 295.65}=2.88\times 10^{-3}[/tex]

Answer:

Atomic element

Explanation:

Carbon is considered an atomic element. Therefore, the correct option is option A among all the given options.

Chemical element carbon has the atomic number six and the letter C assigned to it. It has a tetravalent atom, which means that four of its electrons may be used to create covalent chemical connections. It is nonmetallic. The periodic table's group 14 includes it. The crust of the Earth contains 0.025 percent carbon. There are several ways in which the carbon atoms can connect, giving rise to different allotropes of carbon. Amorphous carbon, diamond, graphite, and fullerenes are examples of well-known allotropes. Carbon is considered an atomic element.

Therefore, the correct option is option A among all the given options.

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Answer:

SO₄²⁻ (aq) + Pb²⁺ (aq) → PbSO₄ (s)

General Formulas and Concepts:

Explanation:

Step 1: RxN

Na₂SO₄ (aq) + Pb(NO₃)₂ (aq) → PbSO₄ (s) + NaNO₃ (aq)

Step 2: Balance RxN

Na₂SO₄ (aq) + Pb(NO₃)₂ (aq) → PbSO₄ (s) + 2NaNO₃ (aq)

Step 3: Ionic Equations

Total Ionic Equation:

2Na⁺ (aq) + SO₄²⁻ (aq) + Pb²⁺ (aq) + 2NO₃⁻ → PbSO₄ (s) + 2Na⁺ (aq) + 2NO₃⁻ (aq)

Cancel out spectator ions.

Net Ionic Equation:

SO₄²⁻ (aq) + Pb²⁺ (aq) → PbSO₄ (s)

Answer:

false

Explanation:

"When a metal reacts with hydrogen carbon dioxide gas is produced" statement is false.

A chemical reaction is a representation of symbols of the elements to indicate the amount of substance and moles of reactant and product.

Generally, metals do not react with hydrogen. But some metals like sodium, potassium, calcium and magnesium force the hydrogen atom to accept the electrons given by these elements and form salt-like ionic solid compounds called metal hydrides.

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Answer:

2H⁺ (aq) + 2OH⁻ (aq) → 2H₂O (l)

General Formulas and Concepts:

Explanation:

Step 1: RxN

HNO₃ (aq) + Ca(OH)₂ (aq) → Ca(NO₃)₂ (aq) + H₂O (l)

Step 2: Balance RxN

2HNO₃ (aq) + Ca(OH)₂ (aq) → Ca(NO₃)₂ (aq) + 2H₂O (l)

Step 3: Ionic Equations

Total Ionic Equation:

2H⁺ (aq) + 2NO₃⁻ (aq) + Ca²⁺ (aq) + 2OH⁻ (aq) → Ca²⁺ (aq) + 2NO₃⁻ (aq) + 2H₂O (l)

Cancel out spectator ions.

Net Ionic Equation:

2H⁺ (aq) + 2OH⁻ (aq) → 2H₂O (l)

Answer:

This question is incomplete but the missing part is in the picture attached.

Explanation:

A mixture of silicon oxide, ammonium chloride and sodium chloride were to be separated. Three separating techniques were used in the experiment; sublimation, decantation and evaporation.

Sublimation is the process in which a substance changes from solid to gas without passing through the liquid phase. Ammonium chloride (NH₄Cl) is a substance that has the ability to sublime and thus was separated first through this property before adding water to the remaining constituents (silicon oxide and sodium chloride) of the mixture. After the addition of water to the mixture, sodium chloride dissolves in this water while silicon oxide does not dissolve in water. The mixture is then left to stand for some minutes so the undissolved sand can settle at the bottom of the mixture and the dissolved salt water can be decanted out so as to have the silicon oxide left in the jar.

The salt solution decanted will have to be evaporated to dryness (to remove the added water) so as to have the solid salt back.

Answer:

Conduction

Explanation:

Conduction is when energy directly travels through a solid to get from one point to another.

A student was holding a metal rod to a candle flame. After a while, he noticed that his hand was getting hot due to conduction.

The definition of conduction is the movement of something together with warmness or energy through a medium or passage. An instance of conduction is using a metallic rod to roast marshmallows on an open hearth and feeling the warmth rise through the rod from the fire for your hand.

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Answer:

The answer is B

Explanation:

Because conduction of heat or electricity occurs through a medium(for eg. The heat from a fire going through a metal pot . So in this example the pot is the medium of conduction).

And in this question the medium of heat conduction is the ground, with the heat moving in an upward motion .

Answer:

A. group

B. period

C. numbers of valence electrons

B. increases

Answer: synthesis

Explanation: hhhhh

Answer:

Synt

Explanation:

Answer: All I know is it's that opposite of B this may not help but I hope it does.

Explanation:

Answer:

C

Explanation:

ap3x

Answer:

D. gravity

hope this helps

Answer:

Each Y atom needs three electrons to complete its octet by forming three bonds to hydrogen. There is one unshared pair of electrons and three bonding pairs of electrons. The bonds in the product are covalent.

Explanation:

Recall that group 5A elements contain five electrons in their outermost shell. These five electrons consists of a lone pair and three electrons that can form three bonds with hydrogen to give YH3 where Y is the group 5A element.

The YH3 molecule contains one lone(unshared) pair of electrons as well as three bonding pairs of electrons. The compounds are covalent.

Answer:

its not A B or C soo choose D *This is what i think*

Answer:

A) something that causes physical pain

hope this helps

Explanation: