The validity of documents was marked by fingerprinting in what time period?


1990 to present

1900-1988

during the 1800s

before the 1800s

The mass, in grams, of 532.0 atoms of cadmium is 9.93 × 10⁻²⁰ g

From the question, we are to determine the mass of the given atoms of cadmium

First, we will calculate the number of moles of cadmium present

Using the formula,

\(Number\ of\ moles = \frac{Number\ of\ atoms}{Avogadro's\ constant}\)

Then,

Number of moles of Cd present = \(\frac{532.0}{6.022 \times 10^{23} }\)

Number of moles of Cd present = 8.83427 × 10⁻²² moles

From the given information,

1 mole of Cd has a mass of 112.41 g

Therefore,

8.83427 × 10⁻²² moles will have a mass of 8.83427 × 10⁻²² × 112.41 g

8.83427 × 10⁻²² × 112.41 = 9.9306 × 10⁻²⁰ g

≅ 9.93 × 10⁻²⁰ g

Hence, the mass, in grams, of 532.0 atoms of cadmium is 9.93 × 10⁻²⁰ g

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It is the simplest whole number ratio of elements in a compound. Molecular formula is n times the empirical formula where n is integers 1,2,... The empirical formula is BH2N.

Empirical formula gives the proportion of the element that is present in a compound. It does not give information about the actual number or the arrangements of the atoms.

n= molecular formula÷ empirical formula

Molecular formula =B\(_3\)H\(_6\)N\(_3\)

Molecular formula = 3×BH2N

Molecular formula =3×empirical formula

Empirical formula = BH2N

Therefore, the empirical formula for this compound B\(_3\)H\(_6\)N\(_3\) is BH2N.

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12.0 grams of \(Pb(NO_3)_2\) would produce 10.1 grams of \(PbCl_2\) precipitate .

To determine the number of moles of lead(II) chloride (\(PbCl_2\)) precipitate that could be produced from reacting 12.0 grams of lead(II) nitrate (\(Pb(NO_3)_2\)), we need to first write and balance the chemical equation for the reaction between these two compounds:

\(Pb(NO_3)_2 (aq) + 2NaCl (aq) = PbCl_2 (s) + 2NaNO_3 (aq)\)

From the balanced equation, we can see that one mole of \(Pb(NO_3)_2\) reacts with 2 moles of NaCl to produce one mole of \(PbCl_2\).

The molar mass of \(Pb(NO_3)_2\) is:

207.2 g/mol (Pb) + 2(14.0 g/mol) + 6(16.0 g/mol) = 331.2 g/mol

To determine the number of moles of \(Pb(NO_3)_2\) present in 12.0 grams of the compound, we can use the following formula:

moles = mass/molar mass

moles of \(Pb(NO_3)_2\) = 12.0 g / 331.2 g/mol = 0.0362 mol

From the balanced equation, we know that 1 mole of \(Pb(NO_3)_2\) reacts to produce 1 mole of \(PbCl_2\). Therefore, 0.0362 moles of \(Pb(NO_3)_2\) will produce 0.0362 moles of \(PbCl_2\)

The molar mass of \(PbCl_2\) is:

207.2 g/mol (Pb) + 2(35.5 g/mol) = 278.7 g/mol

Therefore, the mass of \(PbCl_2\) that could be produced is:

mass = moles x molar mass = 0.0362 mol x 278.7 g/mol = 10.1 g

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Answer: The correct answer is actually: The final temperature is 400 K, while volume is kept constant.

Explanation: Got it right on test!

3 sigma and 3 pieee

okok kkk

1.15 g of Cu are there in a sample of Cu that contains\(1.09*10^{24}\)atoms

The number of grams of Cu in a sample containing\(1.09*10^{24}\)atoms can be determined using Avogadro's number, which is \(6.02*10^{23}\)atoms/mol.

First, we need to calculate the number of moles of Cu in the sample. To do this, we divide the number of atoms by Avogadro's number to get the number of moles:

\(\frac{1.09*10^{24} atoms }{6.02*10^{23} atoms/mol }= 1.81*10^{-1 }mol\)

The sample's mass needs to be determined next. Since copper has an atomic mass of 63.55 g/mol, we can use this to determine the sample's mass:

\(1.81*10^{-1} mol * 63.55 g/mol = 1.15 g\)

Therefore, the sample contains 1.15 g of Cu.

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When you see  or visit grasslands you know that :

Grasslands are a type of vegetation found mostly in areas with favourable weather conditions such as mild summers and right amount of precipitation which provides the grasslands with enough water for proper growth.

Other types of vegetation include :

Desert vegetation expreciences very hot summers and little precipitation which leads to the scarcity of green vegetation, while forest vegetation expreciences a very high level of precipitation.

Hence we can conclude that When you see  or visit grasslands you know that :They have mild to hot summers ,They have a lot of precipitation  

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Answer:

They have little precipitation.

They have cold winters.

They have mild to hot summers.

We can produce more products by;

A. Increasing the concentration of H₂ gas in the reaction vessel

B. Decreasing the temperature in the reaction vessel

C. Removing the H₂O from the reaction vessel as it forms

Water is created through an exothermic process. Heat energy is released when hydrogen gas (H2) and oxygen gas (O2) mix to make water (H2O). An exothermic reaction is characterized by this energy release.

The reaction's overall energy change is negative, which shows that energy is released. The reaction is exothermic because the extra energy is released as heat into the environment.

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Missing parts;

Water can be made using the reversible reaction shown. Which change would

keep this reaction from shifting to form more of the product?

2H₂+022H₂O + energy

A. Increasing the concentration of H₂ gas in the reaction vessel

B. Decreasing the temperature in the reaction vessel

C. Removing the H₂O from the reaction vessel as it forms

D. Increasing the temperature in the reaction vessel

Answer:

Molecules in the skin are moving faster than molecules in the glass.

Explanation:

Put it in your own words.

Answer:

The energy from the ice transferred to the glass.

bnswer

a. O +O / → O₂

b. K + Cl → KCl

c. C + O → CO

d. H + F → HF

e. I + I → I₂

f. S + O + O → SO₂

g. Na + Na + S → Na₂S

h. Li + Cl → LiCl

i. Ca + Br + Br → CaBr₂

j. N + N → N₂

A

Answer:

cake

Explanation:

now here me out, no cake is specified so i can say i want a cake that has pizza on it, take off the pizza, and eat it, this goes with any other food without me having to eat the cake

Answer:

1.06 °C

Explanation:

From the question given above, the following data were obtained:

Mass of gold (M₉) = 10 g

Specific heat capacity of gold (C₉) = 0.129 J/gºC

Initial temperature of gold (T₉) = 24 °C

Mass of water (Mᵥᵥ) = 118 g

Specific heat capacity of water (Cᵥᵥ) = 4.184 J/gºC

Initial temperature of water (Tᵥᵥ) = 1 °C

Equilibrium temperature (Tₑ) =?

The equilibrium temperature of the system can be obtained as follow:

Heat loss by the gold = heat gained by the water

M₉C₉(T₉ – Tₑ) = MᵥᵥCᵥᵥ(Tₑ – Cᵥᵥ)

10 × 0.129 (24 – Tₑ) = 118 × 4.184 (Tₑ – 1)

1.29(24 – Tₑ) = 493.712 (Tₑ – 1)

Clear bracket

30.96 – 1.29Tₑ = 493.712Tₑ – 493.712

Collect like terms

30.96 + 493.712 = 493.712Tₑ + 1.29Tₑ

524.672 = 495.002Tₑ

Divide both side by 495.002

Tₑ = 524.672 / 495.002

Tₑ = 1.06 °C

Therefore, the temperature of the system is 1.06 °C

The amount of heat of the system is measured by a device called a calorimeter. The final temperature of the system will be 1.06 degrees celsius.

The equilibrium temperature is the temperature that follows the law of thermodynamics and is said to be the system that has alike temperatures.  

Given,

Mass of Ag \(\rm (M_{g})\) = 10g

Specific heat capacity of Ag \((\rm C_{g})\) = \(\rm 0.129 J/g^{\circ}C\)

The initial temperature of Ag \((\rm T_{g})\) = \(24 ^{\circ}\;\rm C\)

Mass of water \((\rm M_{w})\) = 118 g

Specific heat capacity of water \((\rm C_{w})\) = \(4.184 \rm \;J/g^{\circ}\;\rm C\)

The initial temperature of water \((\rm T_{w})\) = \(1 ^{\circ}\;\rm C\)

Equilibrium temperature = \((\rm T_{e})\)

The equilibrium temperature can be shown as, heat loss by the gold = heat gained by the water:

\(\rm \rm M_{g}C_{g}(T_{g} - T_{e}) = M_{w}C_{w}(T_{e}-C_{w})\)

Substituting values in the equation:

\(\begin{aligned} 10 \times 0.129 (24 - \rm T_{e}) &= 118 \times 4.184 (\rm T_{e} - 1)\\\\\rm 1.29(24 - T_{e}) &= 493.712 (\rm T_{e} - 1)\\\\524.672 &= 495.002 \;\rm T_{e}\end{aligned}\)

Now divide both the sides by 495.002:

\(\begin{aligned} \rm T_{e} &= \dfrac{524.672 }{495.002}\\\\\rm T_{e} &= 1.06 \;^{\circ}\rm C\end{aligned}\)

Therefore, the final temperature of the system is 1.06 degrees celsius.

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Many island chains were formed as a result of blank volcanism is known as hotspot volcanism.

Hotspot volcanism occurs when a mantle plume, a column of hot and buoyant rock material rising from deep within the Earth's mantle, reaches the surface. These mantle plumes are stationary relative to the moving tectonic plates on the Earth's surface.

As the tectonic plate moves over the stationary hotspot, the mantle plume melts and produces magma. This magma rises through the Earth's crust, creating a volcanic eruption. Over time, repeated eruptions build up layers of lava and volcanic material, forming a cone-shaped volcano. As the tectonic plate continues to move, the volcano becomes inactive, and a new volcano forms above the stationary hotspot.

However, in the case of island chains, the tectonic plate movement carries the volcanoes away from the hotspot. As a result, a trail of extinct volcanoes is left behind, forming a linear chain of islands. Each island in the chain represents a period of volcanic activity at that specific location as the plate moved over the hotspot.

Hotspot volcanism and the formation of island chains provide valuable insights into the dynamics of Earth's mantle and plate tectonics. By studying the age progression of islands in a chain, scientists can gain a better understanding of the movement and speed of tectonic plates and the behavior of mantle plumes deep beneath the Earth's surface.

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The mass of the asteroid is C. 1.2 x \(10^{12}\) Kg

To find the mass of the other asteroid, we can rearrange the equation for the gravitational force between two objects:

F = (G * m1 * m2) / \(r^{2}\)

where F is the force of gravity, G is the gravitational constant, m1 and m2 are the masses of the two asteroids, and r is the distance between them.

Given that the distance between the asteroids is 75000 m, the force of gravity between them is 1.14 N, and one asteroid has a mass of 8 x \(10^{7}\) kg, we can substitute these values into the equation and solve for the mass of the other asteroid (m2):

1.14 N = (6.67430 × \(10^{-11}\) N \(m^{2}\)/\(Kg^{2}\) * 8 x \(10^{7}\) kg * \(m2\)) / \((75000 m)^{2}\)

Simplifying and solving the equation, we find that the mass of the other asteroid (m2) is approximately 1.2 x \(10^{12}\) kg. Therefore, Option C is correct.

The question was incomplete. find the full content below:

Two asteroids are 75000 m apart one has a mass of 8 x \(10^{7}\) kg if the force of gravity between them is 1.14 what is the mass of the asteroid

A. 3.4 x \(10^{11}\) kg

B. 8.3 x \(10^{12}\) kg

C. 1.2 x \(10^{12}\) kg

D. 1.2 x \(10^{10}\) kg

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The two atoms are isotopes of each other are Si with a mass number of 27 and an atomic number 14, and Mg with a mass number of 25 and an atomic number of 12. The correct option is A.

Isotopes are atoms with the same number of protons but differing numbers of neutrons.

They differ in mass, which affects their physical characteristics even if they have nearly identical chemical properties.

An isotope is one of two or more chemical elements that exist in different forms. Varied isotopes of an element share the same atomic number and protons in their nuclei, giving them the same atomic weight.

However, each elemental isotope has a different amount of neutrons, which changes its atomic weight.

They can be referred to as isotopes because Si, which has a mass number of 27 and an atomic number of 14, and Mg, which has a mass number of 25 and an atomic number of 12, both have 13 protons.

Thus, the correct option is A.

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The equation of the reaction leading to the formation of the precipitate is; \(PbCl_{2}(aq) + Na_{2} SO_{4} (aq) ---- > PbSO_{4}(s) + 2NaCl(aq)\)

We define a precipitate as a compound that can be formed as a solid when we mix two aqueous solutions. An aqueous solution is a solution of a substance that have been dissolved in water.

Thus, when we have a mixture of two liquid reactants and then one of the products does separate itself out of the solution then we say that a precipitate has been formed.

In this case, we are to write down the equation of the reaction between aqueous lead (ii) chloride reacts with aqueous sodium sulfate to produce a lead(ii) sulfate. The solid would separate out of the system and we can see the white color of the lead(ii) sulfate.

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Answer:

Explanation:

H2O is a polar molecule

Answer:

polar covalent molecule

Explanation:

the unequal sharing of electrons between the atoms and the unsymmetrical shape of the molecule means that water has two pole a positive and a negative.

Answer:

See explanation

Explanation:

Electron affinity is the energy released when an extra electron is added to a neutral gaseous atom. A negative value of electron affinity indicates that energy is given out and vice versa.

Metals have positive electron affinity since electrons rarely accept electrons, so;

Na(g)+ 1e^- → Na^-(g)      positive

Mg(g)+1e^- → Mg^-(g)      positive

For the last case; Br(g)+ 1e^- → Br^-(g), the electron affinity for the non-metals is negative. hence the answer

Answer: The chocolate has melted, which means it has turn from a solid to a liquid. A liquid has a definite volume but an indefinite shape. Therefore, the correct answer is B.

Priya brought a solid chocolate bar to school to eat as a snack in the afternoon. She left it in her pocket for a few hours. When she took out the chocolate bar to eat it, the bar was was no longer solid. The description that best describes the current state of the chocolate is "The chocolate is now made up of particles packed relatively close together, having an indefinite shape but a definite volume".

There are basically 3 states of matter - Solids, Liquids and gases.

Solid is having definite shape and definite volume, Liquid is having indefinite shape and definite volume and gas is having indefinite shape and indefinite volume.

Liquid and gas states are fluids that can flow easily and their particles are far away from each other.

Water is a liquid, Hydrogen and Oxygen are gases, Ice is a solid.

Given is that Priya left chocolate in her pocket for a few hours. When she took out the chocolate bar to eat it, the bar was was no longer solid.

Therefore, When she took out the chocolate bar to eat it, the bar was was no longer solid. The description that best describes the current state of the chocolate is "The chocolate is now made up of particles packed relatively close together, having an indefinite shape but a definite volume".

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The pH of the solution or enzyme amylase affect is directly affected by fat digestion. Set has a neutral PH, but when fats are digested by lipase, they are converted into fatty acids. The presence of fatty acids can either decrease or stimulate the pH, resulting in an increase in the acidity of the solution. PATHWAY - Fat Digestion - Produre, - Fatty Acid Alkali Sodium Carbonate Increasing the pH

The enzyme alpha-amylase is in charge of digesting or breaking down starch. Crackers are a type of food that contains a lot of starch. When the salivary glands release starch, alpha-amylase begins digesting it in the mouth. It degrades starch into smaller chains of two or three glucose molecules.Proteins are enzymes that aid inside the speeding up of digestion, or the synthetic reactions that take place in our carcasses. Some substances are formed whereas others are broken. Enzymes are present in all living items. Enzymes are produced naturally by in out bodies. However, enzymes may also be found in factory - made products and food. Pepsin, for example, is an integral part of gastric secretions that aids in the breakdown of bits of food in the stomach. Similarly, the pancreatic amylase, which is found in saliva, gets converted starch into carbohydrates, which aids in digestion. The enzyme thrombin is used in medicine to promote wound healing.

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In order to find the hydronium ion concentration in this solution, we have to find the pH and we are given the pOH of the reaction, 8.30. The pH and pOH can be used in the same formula to equal 14, which is the highest value of pH, within normal conditions, and the pH and pOH are always opposites in this scale, therefore the formula will be:

pH + pOH = 14

pH = 14 - 8.30

pH = 5.7

Now that we have the pH, we can find the [H3O+], which can be found in the following formula:

[H3O+] = 10^-pH

[H3O+] = 10^-5.7

[H3O+] = 1.99*10^-6, letter B

Selection is the process by which we filter out irrelevant information and focus on the information that is most relevant to us.

For example, when we walk down a busy street, we may not pay attention to every detail of every building or person we pass by. Instead, we might focus on things that stand out, such as a bright billboard or an interesting conversation nearby.

Regarding stereotypes, one common example is the belief that all individuals from a certain race, gender, or religion share certain characteristics or behaviors. This stereotype is often based on limited or inaccurate information and can lead to biased judgments and discrimination. It's essential to recognize and challenge our own stereotypes to avoid unfairly treating others based on their group membership.

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The equation for the reaction that goes with this equilibrium constant is HCLO + H₂O  ------> H₃O ⁺ + Cl⁻.

The equilibrium consistent of a chemical reaction is the price of its response quotient at chemical equilibrium, a nation approached through a dynamic chemical gadget after sufficient time has elapsed at which its composition has no measurable tendency closer to in addition alternate.

The equilibrium consistency may be described as the ratio between the quantity of reactant and the amount of product that is used to determine chemical conduct. At equilibrium, the fee of the forward response = price of the backward reaction.

The equilibrium constant of a chemical response is the price of its response quotient at chemical equilibrium, a state approached via a dynamic chemical system after sufficient time has elapsed at which its composition has no measurable tendency in the direction of addition exchange.

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We have the next reaction

2C4 H10 + 13O2

And we must determine how many atoms of oxygen are needed on the product side.

To determine the number of atoms of oxygen that are need on the product side we need to use the law of the conservation of mass which says that matter cannot be created or destroyed. In chemical equations, the number of atoms of each element in the reactants must be the same as the number of atoms of each element in the products.

So, the number of atoms of oxygen that are need on the product side is the same number of atoms of oxygen on the reactants side.

Then, the number of atoms of oxygen on the reactants side is obtained multiplying the coefficient times the oxygen subscript

So, the are 26 atoms of oxygen in the reactants.

Finally, using the law of the conservation of mass 26 atoms of oxygen are needed on the pro

Answer:

The equation is balanced

Explanation:

There are 3Mg,2N,12H,6O and on the other side its the same amount on the other side

Answer:

\(\huge\boxed{\sf 2.27\ atm = 1,725\ mm\ of\ Hg}\)

Explanation:

We know that:

1 atm = 760 mm of Hg (Standardly)

Multiply both sides by 2.27

2.27 atm = 760 * 2.27 mm of Hg

2.27 atm = 1,725 mm of Hg

\(\rule[225]{225}{2}\)

Hope this helped!

Complete Question

The complete question is shown on the first uploaded image

Answer:

The rate constant is  \(k_d = 3.44*10^{10} \ L \cdot mol^{-1} s^{-1}\)

Explanation:

From the question we are told that

The values for an enzyme is given as

     \(D_1 = 1.00 *10^{-7} \ cm^2 s^{-1}\)

     \(r_1 = 40.0 \r A = 40*10^{-8} cm\)

The values of a small molecular substrate is

     \(D_2 = 1.00 *10^{-5} \ cm^2 s^{-1}\)

      \(r_2 = 5.00 \r A = 5.00*10^{-8} \ cm\)

The equation relating the rate constant  is

      \(k_d = 4 \pi N_A (D_1 +D_2) (r_1 +r_2)\)

substituting values

      \(k_d = 4 \pi (6.022 *10^{23})(1 *10^{-7} * 1*10^{-5} (40*10^{-8} + 5*10^{-8}))\)

     \(k_d = 3.44*10^{10} \ L \cdot mol^{-1} s^{-1}\)

Answer:

This idea helps students explain why more rain forms over West Ferris than East Ferris. ... Therefore, when students explain that water vapor condenses higher in the atmosphere, they are actually explaining that water vapor condenses high in the troposphere, which is relatively low in the atmosphere.

Explanation: