A compound was found to contain 90.6% lead (Pb) and 9.4% oxygen. What is the empirical formula for this compound?

Answer:

C. 0.5 cal/g°C

Explanation:

Using the following equation:

Q = m × c × ∆T

Where;

Q = amount of heat absorbed/released (calories)

m = mass of substance (g)

c = specific heat capacity (calg/°C)

∆T = change of temperature (°C)

According to the information provided in this question;

m = 10g

c = ?

∆T = 20°C

Q = 100cal

Using Q = m × c × ∆T

c = Q ÷ (m × ∆T)

c = 100 ÷ (10 × 20)

c = 100 ÷ 200

c = 0.5 cal/g°C

Answer:

B

Explanation:

During the first half of the reaction there was an increase in the rate of reaction due to the high concentration of the reactants. But as the reaction continues we witness a decrease in the amount of reactants which lowers the rate.

Answer:

B.  The concentration of reactants decreased while the concentration of product increased.

Explanation:

took the test :)

Answer:

Specific heat capacity is measured by determining how much heat energy is needed to raise one gram of a substance one degree Celsius. The specific heat capacity of water is 4.2 joules per gram per degree Celsius or 1 calorie per gram per degree Celsius

Explanation:

Explanation:

i dont know 8th and i am not sure baout carbonic acid in 10 th but they are balanced

Answer:

They form salt + water.

and the rxn is known as neutralisation rxn

Answer:

When an acid and a base are placed together, they react to neutralize the acid and base properties, producing a salt. Acid-base reactions that do not occur in water usually also produce salts, but they may also produce complex ions.

Helpful Link:

https://sciencing.com/happens-acid-base-combined-5132830.html

Answer:

the product of q in the reaction below is Nacl

Answer:

International System of Units (SI)

Explanation:

I hope it helps :)

Answer:

The last one

Explanation:

Charges are balanced in a redox reaction

The species that is reduced in the reaction is Fe. Option B

The process by which an atom gains an electron, thereby lowering or decreasing its oxidation number. Basically, the positive character of the species is reduced. Reduction occurs when an atom gains one or more electrons during a chemical reaction. This means that the oxidation number decreases. This is when an atom gains an electron because electrons have a negative charge.

Acquires a negative charge that reduces the oxidation number. Reduction involves a half-reaction in which a chemical species reduces its oxidation number, usually by gaining an electron. The other half of the reaction involves oxidation in which electrons are lost. Reduction and oxidation together form a redox reaction. As the oxidation number increases, the atom is oxidized, and as the oxidation number decreases, the atom is reduced.

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Answer: Ag+

Explanation: I just took the test.

Answer:

a) Barney wants to repeat the rutheford experiment

b) the element will be in row 8 column 1 being an alkali metal

c) it should be a radioactive element, with a lot of mass

Explanation:

n this exercise they indicate that the particle Gz has atomic number 119 and atomic mass 305 amu, when reviewing the element periodicity table with this atomic number it has not yet been discovered, it should be in row 8 column 1 therefore it should be an alkali metal .

Therefore, it has only one electron in its last orbit.

a) Barney wants to repeat the rutheford experiment

b) the element will be in row 8 column 1 being an alkali metal

c) it should be a radioactive element, with a lot of mass

Answer:

The reactants for rust are iron ,water and oxygen while the products are hydrated iron oxide

Explanation:

4Fe+3O2+2H2O---->2Fe2O3.H2O

Answer:

This is true.

Explanation:

R should be 0.0821

Good luck!

Answer:

It's nitrogen

Explanation:

cuz it has valence 3 and  a diatomic gas at room temperature

Element X must be nitrogen.

The general formula AlX indicates that aluminum (Al) is reacting with a nonmetallic element represented by X to form a compound.

Since the compound AlX is said to be a diatomic gas at room temperature, it aligns with nitrogen (N2), which is a diatomic gas and a nonmetal.

Among the given options, nitrogen is the diatomic gas that best fits this description.

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Answer:

liquid form

Explanation:

am i right? if right like

Answer:

semi-liquid at room temperature

Temperature is measured in Kelvin..

Answer:

camphor sublimates salt is soluble in water while sand does not sublime and does not dissolve in water you first heat the mixture in a beaker covered with a watch glass camphor will then accumulate on the watch glass then you dissolve the remaining mixture of sand and salt salt will dissolve forming a salt solution then you filter using a filter paper and a beaker the residue on the filter paper is sand while the filtrate is salt solution you then heat the salt solution so that it can evaporate leaving salt particles thus you will have obtained salt sand and camphor

D. the pupil or the dark portion at the center of the eye

Answer:

a measuring cylinder containing water only.

Explanation:

If we want to measure the volume of an irregular object. We need a properly calibrated measuring cylinder filled with water of known volume.

The irregular object is now inserted into the measuring cylinder containing water and the change in the volume of water is noted. The volume of the irregular object is now obtained as;

New volume of water - initial volume of water.

Hence, only a measuring cylinder filled with water is required to measure the volume of a small irregularly- shaped stone.

Answer:

A ball is thrown straight up from a rooftop 320 feet high. The formula below describes the ball's height above the ground, h, in feet, t seconds after it was thrown. The ball misses the rooftop on its way down and eventually strikes the ground. How long will it take for the ball to hit the ground? Use this information to provide tick marks with appropriate numbers along the horizontal axis in the figure shown.

h=-16t^2+16t+320

Answer:

các oxit đồng khi nó tiếp xúc với không khí. nó phản ứng đặc biệt với oxy trong không khí (không phải hơi ẩm), và tạo ra nấm mốc

Answer:

depends on the element it's reacting with..

Explanation:

if the another element requires less energy to loose electron then zinc will become negatively charged and hence becomes acidic radical..

normally if it is reacting with element with valency 4 and Atomic number less than it(Ti,Si,C) then it will lose electron and gain positive sign and henve becomes basic radical..

Answer:

the degree of ionization in water is high

Explanation:

The term pH is defined as the negative logarithm of hydrogen ion concentration.

Hence;

pH = -log[H^+]

The pH scale shows the degree of acidity or alkalinity of a solution. A solution of pH 1 is a strong acid. A strong acid dissociates completely in solution.

Hence, acid U has a high degree of ionization in water.

[tex]\sf\bold{❍ Given:-}[/tex]

NaOH is dissolved in certain kilograms of solvent and molality of solution 0.5m.

Again , same among of NaOH is dissolved in 100 grams of solvent than initial , then molality becomes 0.625m.

$\space$

Now lets find the amount of NaOH and the initial mass of solvent.

Let,

$\space$

$\sf\bold{ ❍ We\:know,}$

$\sf{Molality(m)=}$ $\sf\dfrac{No.of\:moles\:of\:solute}{No.of\:solvent\:in\:kg}$

$\space$

$\sf\bold{Putting\:the\:formula:-}$

$\space$

$\sf\huge\underline\bold{ ❍Case:1}$

$\space$

$\longmapsto$ $\sf\small{0.5}$ $\sf\dfrac{x}{y}$

$\space$

$\longmapsto$ $\sf{0.5y = x }$

$\space$

$\longmapsto$ $\sf{multiply\:by\:2→ y = 2x}$

$\space$

$\sf\huge\underline\bold{ ❍Case:2}$

$\space$

$\longmapsto$ $\sf\small{0.625}$ $\sf\small\dfrac{x}{y}$ = $\sf\dfrac{x}{y=100g}$

$\space$

$\longmapsto$ $\sf\small{0.625}$ $\sf\dfrac{x}{y-100/1000kg}$ = $\sf\dfrac{x}{y-0.1kg}$

$\space$

$\longmapsto$ $\sf{0.625(y-0.1kg)=x}$

$\space$

$\longmapsto$ $\sf{0.625y-0.0625=x}$

$\space$

$\sf\small\bold{By\:putting\:the\:value\:of \:"x" we\: get:}$

$\space$

$\longmapsto$ $\sf{0.625(2x)-0.0625 = x}$

$\space$

$\longmapsto$ $\sf{1.25x 0.0625 = x}$

$\space$

$\longmapsto$ $\sf{1.25x - x = 0.0625}$

$\space$

$\longmapsto$ $\sf{0.25x = = 0.0625}$

$\space$

$\longmapsto$ $\sf\small{x=}$ $\sf\dfrac{0.0625}{0.25}$= $\sf\bold{x=0.25}$

$\space$

$\sf{So,y=2(x)=2\times0.25=}$ $\sf\bold{y=0.5}$

$\space$

$\sf\small{Initial\:mass\:of\:solvent:0.5kg=500g}$

$\space$

$\sf{Now,}$

Amount of NaOH=

$\space$ $\space$ $\space$ $\space$ $\space$ $\sf{=x\times molar\:mass}$

$\space$ $\space$ $\space$ $\space$ $\space$ $\sf{=0.25\times 40=10}$

$\space$

$\sf\underline{\underline{ ⚘ Hence,amount\:of\:NaOH=10kg}}$

_______________________________

Answer:

It should be the answer D. A type of atom

Explanation:

A model is a "synthetic coordination entity that closely approaches the properties of a metal ion in a protein"

An ion is a charged atom.

Answer:

[tex]\boxed {\boxed {\sf 8.0 \ M \ NaCl}}[/tex]

Explanation:

Molarity is a measure of concentration in moles per liter, therefore the formula is:

[tex]molarity= \frac{moles \ of \ solute}{lites \ of \ solution}[/tex]

There are 2.0 moles of solute or sodium chloride dissolved in 0.25 liters of water or solution.

Substitute these values into the formula.

[tex]molarity= \frac{ 2.0 \ mol \ NaCl}{0.25 \ L}[/tex]

Divide.

[tex]molarity=8 \ mol \ NaCl / L[/tex]

Molarity is measured in molars or M. 1 molar is equal to 1 mole per liter, so our answer is equal to 8 molars.

[tex]molarity= 8 \ M \ NaCl[/tex]

The original measurements of moles and liters have 2 significant figures, so our answer must have the same. For the number we calculated, that is the tenths place. There are no numbers to round, so we add a 0 in the tenths place.

[tex]molarity= 8.0 \ M \ NaCl[/tex]

The molarity of the solution is 8.0 M NaCl.

Answer:

Nucleus is the answer

A micrograph of animal cells, showing the nucleus (stained dark red) of each cell. Known as the cell's “command center,” the nucleus is a large organelle that stores the cell's DNA (deoxyribonucleic 

Answer:

nucleus is the part of a cell directs the cells Activities and holds it's DNA

Answer:

yes they were made to carry thousands of lb high up

Answer:

C

Explanation:

C. Adding a catalyst would increase the reaction rate.

A catalyst is a substance that increases the rate of a chemical reaction by lowering the activation energy required for the reaction to occur.

A catalyst enhances the probability of successful collisions between reactant molecules, which raises the pace of the reaction by offering an additional avenue for the reaction to occur.

As there would be fewer reactant molecules accessible to react with one another, decreasing reactant concentrations would result in a slower pace of reaction.

Due to the fact that chemical reactions often require energy to take place, eliminating heat from the system would also slow down the reaction rate. A lower value for k would result in a lower rate constant, which would lower the response rate.

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Answer:

2 Na atoms

Explanation: