While swimming at the lake, you discover that the water is cooler the
deeper you dive. Why?

There are numerous ways to determine whether lead is present in an ore. Atomic absorption spectroscopy is a popular approach. With this method, an ore sample is dissolved in acid and then atomized in a flame or plasma.

The sample's atoms will absorb light at particular wavelengths that are peculiar to the element under investigation. The amount of light absorbed can be used to calculate how much lead is present in the sample. Inductively coupled plasma mass spectrometry and X-ray fluorescence spectroscopy are further techniques. It is crucial to remember that these procedures call for specialized tools and training, thus they ought to only be carried out in a lab by qualified experts.

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The mass of the solution formed when 20 g of sugar dissolved in 150 g of tea is 170 g.

The net mass of solution is calculated as the algebraic addition of the mass of the solute which is stirred into the mass of the solvent.

During the formation of solution, the sugar molecules are dissolved into tea in which sugar molecules fitted into the intermolecular spaces present between the water molecules of the tea and form a homogenous mixture.

Solvent is the substance or mixture which present in large amount in the solution.

Solute is the substance or mixture which present in small amount in the solution.

Given,

Mass of solute (sugar) = 20g

Mass of solvent (tea) = 150g

Total mass of solution = 20 + 150

= 170g.

Thus we concluded that the mass of the solution formed when 20 g of sugar dissolved in 150 g of tea is 170 g.

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Explanation:

28.09 g of silicon contains 6.02×1023 6.02 × 10 23 silicon atoms.

1 mole = 6.02.10²³ particles (atoms, moleculs, ions)

mole Si = mass : molar mass

mole Si = 28.09 : 28.09 = 1

number of atoms = 1 x 6.02.10²³ = 6.02.10²³ atoms

Answer:

D

Explanation:

I'm not 100% sure on this but I am pretty confident that it's D or C I'm 98% sure it's D

Explanation:

H is 1 mole of hydrogen

2H is 2 moles of hydrogen

Step 1 - Understanding the types of heat transfer

There are three types of heat transfer: conduction, convection and irradiation. Let's see how each one works:

a) Conduction: is when a very hot substance enters in contact with a cooler substance. The atoms in the hotter substance are moving with a greater velocity and will therefore collide with the atoms of the cooler substance.

b) Convection: it happens especially in liquids and air (fluids). The liquid is warmed up at the bottom first, via conduction. The heated bottom thus changes its density: it becomes less dense, and go up. This process repeats itself several times, warming the whole liquid.

c) Irradiation: when something is put near a heat source, but do not touch it directly. In this case, there's no direct atom collision, but indirect: the rapid atoms of the heat source collide with atoms in the air which then collide with the atoms in the object that is being heated.

Step 2 - Discovering the type of heat transfer in each scenario

In the first scenario, the water at the bottom is in direct contact with the pan. Therefore, water molecules will directly collide with "pan" molecules (probably aluminum atoms or other materials). But there's also convection. The water is not heated only by conduction.

In the second scenario, the hands are near the Bunsen burner, but not directly touching it. What is happening here is then heat irradiation, not conduction.

In the third scenario, the hand is touching the object (the handle of the pan). Even though handles are made of material that poorly conduct heat, it will increase its temperature, at least a little bit. When we touch it, we can feel it is hotter than before. In this case, only conduction is involved (from the handle to our hand). In this case atoms are directly colliding and this is the only source of heat.

Finally, in the last scenario, we also have a case of irradiation: the pan with water is near the heat source, but not directly touching it.

Step 3 - How to set an experiment

In science in general, anytime we want to investigate some effect it is good manners to investigate a system controling all other effects. We want to investigate a variable at a time.

Therefore, while both scenario 1 and 3 involve conduction, scenario 1 also involves convection, which could be a problem to a experiment intending to study conduction only.

The best experiment would be then scenario 3, hands touchind the handle of pan siting in a Bunsen burner.

Entropy is related to the degree of disorder of a process. If disorder increases, entropy increases.

Now, in a chemical reaction this disorder can be associated with the dissolution of a solid in a liquid, or by the increase in moles when the reaction is at the gaseous phase.

We have 3 reactions that occur in the gas phase, A, B, and D. All these reactions have as products less number of moles with respect to the reactants, so in these three reactions the entropy does NOT increase, it decreases

Reaction C refers to the dissolution of a solid reactant. This dissolution represents an increase in entropy.

Therefore, the answer will be: C. KNO3(s) → K+ (aq) + NO3-(aq)

Answer:

attached below

Explanation:

write the chemical equations for the test  and confirmation test

i.e.

i)Chemical equation for main copper test

ii)Chemical equation for copper confirmation test

iii)Chemical equation for main bismuth test

iv) Chemical equation for bismuth confirmation test

attached below are the chemical equations for the test and confirmation test

The correct answers are triple point, Carbonic acid, Antibody production, endocytosis of a virus by a phagocyte lymphocyte. E. T lymphocyte activation and clonal expansion, Corpus luteum and Aorta.

In a phase diagram, triple point is the term used for a substance held at a temperature and pressure where the solid ,liquid and gaseous states of substance exist simultaneously.

Carbonic acid is a substance that is responsible for donating H+ ions to act as a buffer when blood pH rises.

Antibody production, endocytosis of a virus by a phagocyte lymphocyte. E. T lymphocyte activation and clonal expansion are specific immune responses.

Corpus luteum is a mass within the ovary that secrets hormones to maintain the uterine lining during pregnancy.

A myocardial infarction affects Aorta blood vessels of the heart.

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The final volume is 30.62L

Volume is the amount of space occupied by a three-dimensional figure as measured in cubic units

Here given data is

NH₄NO₃ = 17.5 g

Concentration = 1.75 M

We have to calculate final volume solution = ?

So Concentration = mass/volume

Volume = concentration × mass

Volume =  1.75 M ×  17.5 g

Volume = 30.62L

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The octet rule describes an atom's propensity to favour eight electrons in its valence shell. Atoms with fewer than eight electrons are more likely to interact with one another and create more stable molecules.

Based on the observation that the atoms of the main group elements tend to participate in chemical bonding in a way that each atom of the resulting molecule has eight electrons in the valence shell, this theory was developed. Only the core group elements are subject to the octet rule.

Because both atoms receive a full valence shell as a result of the sharing, the octet rule is essential in covalent bonding.

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The question is incomplete, the complete question is;

Using the following equation 2 NaOH(aq) + H2SO4(aq) → 2 H2O(aq) + Na2SO4(aq) how many grams of sodium sulfate will be formed if you start with 200 grams of sodium hydroxide and you have an excess of sulfuric acid

Answer:

355.1 g

Explanation:

The equation of the reaction is;

2 NaOH(aq) + H2SO4(aq) → 2 H2O(aq) + Na2SO4(aq)

We have been told that H2SO4 is in excess so NaOH is the limiting reactant. Therefore;

Number of moles in 200g of NaOH = 200g/40g/mol = 5 moles

So;

2 moles of NaOH yields 1 mole of Na2SO4

5 moles of NaOH will yield 5 * 1/2 = 2.5 moles of Na2SO4

Molar mass of Na2SO4 = 142.04 g/mol

Mass of Na2SO4= 2.5 moles * 142.04 g/mol = 355.1 g

The solutions for all cases are,

(a) The reaction will favor the formation of the weak acid HA and hydroxide ions OH-.

(b) K = [HA][OH-] / [A-], leading to a value of K that is less than 1.

(c) A- is a weak base since it has a low tendency to accept protons (act as a base) due to the presence of its conjugate acid HA.

For the given Cases;

a) The equilibrium will lie to the left since the anion A- is the conjugate base of a weak acid, indicating that it will have a weak tendency to accept protons (act as a base). Therefore, the reaction will favor the formation of the weak acid HA and hydroxide ions OH-.

b) The value of the equilibrium constant expression (K) can be expressed as follows:

K = [HA][OH-] / [A-]

Since HA is a weak acid, it will not dissociate completely in solution, leading to a low A-concentration. As a result, the denominator of the expression will be relatively small, leading to a value of K that is less than 1.

c) Since the equilibrium lies towards the weak acid side, the hydroxide ion OH- will have a relatively low concentration, indicating that it is a weak base. Therefore, A- is a weak base since it has a low tendency to accept protons (act as a base) due to the presence of its conjugate acid HA.

Hence,

(a) The reaction will favor the formation of the weak acid HA and hydroxide ions OH-.

(b) K = [HA][OH-] / [A-],leading to a value of K that is less than 1.

(c) A- is a weak base since it has a low tendency to accept protons (act as a base) due to the presence of its conjugate acid HA.

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Answer:

1st one is...

Explanation:

The 1st one is change in size or shape. 2nd one is formation of precipitate. 3rd one is physical change. 4th one is formation of gas.

Answer:

Physical weathering is caused by the effects of changing temperature on rocks, causing the rock to break apart.

Explanation:

Freeze-thaw occurs when water continually seeps into cracks, freezes and expands, eventually breaking the rock apart.

Answer:

2

Explanation:

the number of H is 1, it means the only electron is on the energy level (1st level, s-electron). All the elements have 2 s-electrons on the 1st energy level.

BaSO4 (s) + Cu(NO3)2 (aq)  and KCl (s) + Mg3(PO4)2 (s) is the product of given precipitation reactions.

Ba(NO3)2 (aq) + CuSO4 (aq) → BaSO4 (s) + Cu(NO3)2 (aq)

 K3 PO4 (aq) + MgCl2 (aq) → KCl (s) + Mg3(PO4)2 (s)

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Answer:

A sample of a gas (5.0 mol) at 1.0 atm is expanded at constant temperature from 10 L to 15 L. The final pressure is 0.67 atm.

Step by Step Explanation?

Boyle's law states that in constant temperature the variation volume of gas is inversely proportional to the applied pressure.

The formula is,

P₁ x V₁ = P₂ × V₂

Where,

P₁ is initial pressure = 1 atm

P2 is final pressure = ? (Not Known)

V₁ is initial volume = 10 L

V₂ is final volume = 15 L

Now put the values in the formula,

\begin{gathered}\rm 1\times 10 = P_2\times 15\\\\\rm P_2 = \frac{10}{15\\} \\\\\rm P_2 = 0.67\end{gathered]

Therefore, the answer is 0.67 atm.

Answer:

d

Explanation:

Answer:C is the answer

Explanation:

Answer:

b, c, e

Explanation:

Inorganic compounds usually lack carbon.

Inorganic compounds are not associated with or made from living things.

Inorganic compounds include salt and water​.

Answer:

yes the answer id bce

Explanation:

Answer:

C

Explanation:

[Ne]3s23p1

Answer:

C

Explanation:

Answer: I think its B

Explanation:

please lmk if I'm wrong.

Empirical formula mass

Molar mass=232.2g/mol

Find n

Molecular formula

Find the empirical formula mass

Find n

Round to nearest whole

Molecular formula

The first thing to do when solving this problem is to make sure the equation is balanced:

We want to know the maximum amount of SO2 that can be produced.

Given:

mass of H2S = 1060 g

mass of O2 = 2890 g

We have to find the limiting reagent, and use its molar ratio to find number of moles of SO2, then we can find the mass produced.

H2S:

n = m/M where n is the number of moles, m is the mass and M is the molar mass. Molar mass can be found by adding atomic masses of H2 + S.

n = 1060 g/34,1 g/mol

n = 31.085 mol

O2:

n = m/M

n = 2890 g/31.998

n = 90.318 mol

So Oxygen has a higher number of moles, so it is reactant in excess and H2S the limiting reactant/reagent since it has less number of moles.

We can use the stoichiometry to find the molar ratios of H2S:SO2. The molar ratio is 2:2.

Therefore the number of moles of SO2 = 31.085 x (2/2) = 31.085 mol

From the number of moles, we can find the mass of SO2.

m = n x M

m = 31.085 mol x 64,066 g/mol

m = 1991.5 g of sulfur dioxide will be produced.

The e/m value of He+ ions was found to be 1.96 x 10^7 C/kg. The e/m value of an electron is 1836 times greater than the e/m value of a helium ion. 1836 times greater is the correct answer.option B.

The e/m value of an electron is greater than the e/m value of a helium ion. The e/m value of an electron is determined by the relationship between the charge of the electron and its mass.

The charge-to-mass ratio is determined by the force of the magnetic field on the charged particle and its velocity.

This value is usually expressed in units of coulombs per kilogram (C/kg).

According to Thomson's experiment, cathode rays were shown to be made up of negatively charged particles that were later named electrons.

The charge-to-mass ratio of these particles was determined by deflecting them with a magnetic field.

The value of e/m was found to be 1.76 x 10^11 C/kg.

The charge-to-mass ratio of He+ ions was discovered using a similar method.

When a beam of He+ ions is fired through a magnetic field, it deflects in the opposite direction to the electron beam.

The e/m value of He+ ions was found to be 1.96 x 10^7 C/kg.

Hence, the e/m value of an electron is 1836 times greater than the e/m value of a helium ion.option B.option B.

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The ideal gas law may be used to determine the volume of oxygen created in the electrolysis that produces 548 litres of hydrogen at STP (Standard Temperature and Pressure). PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the gas constant, and T is the temperature, according to the ideal gas equation.

The pressure is 1 atm, the temperature is 273 K, and the number of moles of hydrogen is 548/22.4 = 24.5 in this example. We may compute the volume of oxygen created by rearranging the ideal gas law: V = nRT/P = 24.5*0.082*273/1 = 483.3 litres.

As a result, the volume of oxygen created in the electrolysis at STP that produces 548 litres of hydrogen is 483.3 litres.

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Taking into account the definition of molarity, the number of moles of MgCl₂ present in 60.0 mL of 0.100 M MgCl₂ solution is 0.006 moles.

Molarity is a measure of the concentration of a solute in a solution and indicates the number of moles of solute that are dissolved in a given volume.

The molarity of a solution is calculated by:

molarity= number of moles of solute÷ volume

Molarity is expressed in units moles/L.

In this case, you have:

Replacing in the definition of molarity:

0.100 M=number of moles of MgCl₂÷ 0.06 L

Solving:

0.100 M × 0.06 L= number of moles of MgCl₂

0.006 moles= number of moles of MgCl₂

Finally, the number of moles of MgCl₂ is 0.006 moles.

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