Which of these is an indication that a chemical reaction has occurred?

Select all that apply:

melting of a substance

boiling of a substance

formation of a new gas

formation of a precipitate

a new smell is given off

heat is released

Answer: BaC2N2

Explanation: You start with your grams and divide them by their mass to get moles.

9.48g/137.33=.0690

1.66/12.01=.1382

1.93/14.007=.1379

You then take your moles and divide them by the smallest mole.

.0690/.0690=1

.1382/.0690=2.002

.1379/.0690=1.999

You then multiply them by a whole number to get them to be whole numbers, in this case you can use one.

1*1=1

2.002*1=2.002- round down to 2

1.999*1=1.999- round up to 2.

Final answer:

The empirical formula for the compound composed of barium, carbon, and nitrogen is found by converting the given masses to moles, determining the simplest whole number ratio of these moles, and combining them to form BaC2N2.

Explanation:

To determine the empirical formula for a compound with a given mass analysis, we first need to convert the mass of each element to moles by dividing by their respective atomic masses. The elemental masses given for the substance are 9.48 g of barium (Ba), 1.66 g of carbon (C), and 1.93 g of nitrogen (N).

We calculate the moles of each element as follows:

Moles of Ba = 9.48 g ÷ 137.33 g/mol (atomic mass of Ba) = 0.069 moles of Ba

Moles of C = 1.66 g ÷ 12.01 g/mol (atomic mass of C) = 0.138 moles of C

Moles of N = 1.93 g ÷ 14.01 g/mol (atomic mass of N) = 0.138 moles of N

Next, we determine the simplest whole number ratio of moles of each element:

The ratio for Ba is 0.069 ÷ 0.069 = 1

The ratio for C is 0.138 ÷ 0.069 = 2

The ratio for N is 0.138 ÷ 0.069 = 2

From these ratios, we find the empirical formula of the compound to be BaC2N2. This formula represents the simplest whole number ratio of elements within the compound.

Answer:

I am so sorry I wish I could help

Explanation:

maybe use a calculator

The percent error in the measured density of alcohol, with a measured value of 0.8023 g/mL and a true value of 0.7980 g/mL, is approximately 0.539%.

To calculate the percent error for the measured density of alcohol compared to the true value, you can use the following formula:

Percent Error = ( |Measured Value - True Value| / True Value ) 100%

Applying this formula to the given values:

We calculate the absolute difference and then divide by the True Value:

0.8023 g/mL - 0.7980 g/mL| = 0.0043 g/mL

Now divide by the True Value of 0.7980 g/mL and multiply by 100:

(0.0043 g/mL / 0.7980 g/mL) 100%
approximately 0.539%

Therefore, the percent error in the measurement of the density of alcohol is approximately 0.539%.

Answer:my answer  is correct

Explanation:

The box has been used to keep the food hot has been a bad conductor of heat. The heat has been entrapped within the box that helps for the food to keep hot.

The material used for the box to keep the food hot has been rubber. Thus, option C is correct.

The conductor is the materials that has been able to transfer the energy. The insulators are the materials that do not allow the transfer of energy.

The metals have been considered as good conductor of energy. Thus, with the use of stainless steel, aluminum foil, or even glass results in the transfer of energy from food to the environment resulting in cooling the food.

The rubber has been a bad conductor of energy and is a good insulator. It has been able to entrap the heat energy in the box and keeps the food hot. Thus, option C is correct.

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The number of moles of strontium phosphite in a 321.1-gram sample is calculated by dividing the mass by the molar mass of strontium phosphite. The molar mass is found using the molecular formula Sr3(PO3)2 and the atomic masses from the periodic table.

To calculate the number of moles of strontium phosphate from 321.1 grams, we must first know its molar mass, which can be calculated using the periodic table. Once we have the molar mass, we can divide the mass of the strontium phosphate by this number to find the moles.

The formula for strontium phosphate is Sr3(PO3)2. We can calculate the molar mass as follows: (Sr: 87.62 g/mol * 3) + (P: 30.97 g/mol * 2) + (O: 16.00 g/mol * 6) = 452.34 g/mol. Then we use this molar mass to find the number of moles:

Moles of strontium phosphite = 321.1 g / 452.34 g/mol To answer the question accurately, perform the division to obtain the moles, which will be expressed in three significant figures. This approach is similar to how you would calculate moles for other substances by using their respective molar mass.

Answer:

Explanation:

The gas law used to solve the problems is Charles's law . It states with no pressure or energy change, the volume of an ideal gas is directly proportional to its temperature in Kelvin.

A gas occupies 547 L at 331K.

So its volume at 376K is

= 547 / 331 * 376

= 621.37 L

The gas law used to solve the problem is Boyle's law . It states with no temperature or energy change, the volume of an ideal gas is inversely proportional to its pressure.

A gas occupies 97 mL at 130 kPa.

So its volume at 225 kPa is

= 97 * 130 / 225

= 56.04 mL

#1

Apply charles law

[tex]\\ \rm\Rrightarrow V1T2=V2T1[/tex]

[tex]\\ \rm\Rrightarrow V2=\dfrac{V1T2}{T1}[/tex]

[tex]\\ \rm\Rrightarrow V2=\dfrac{547(376)}{341}[/tex]

[tex]\\ \rm\Rrightarrow V2=603.1L[/tex]

#2

Apply boyles law

[tex]\\ \rm\Rrightarrow P1V1=P2V2[/tex]

[tex]\\ \rm\Rrightarrow 130(97)=225V2[/tex]

[tex]\\ \rm\Rrightarrow V2=56.04mL[/tex]

A: Molar Mass

Because the mass is distributed along a specific matter, depending on the kinetic energy used, it will directly be connected to the atoms mass

Answer:

Golgi body

Explanation:

Answer:

cell wall i think

Explanation:

i think because bacteria dont have a cell wall

Answer:

1. Blood sugar will decrease because glucagon increases blood sugar when it falls too low.

Answer:

When dissolved in water, acids donate hydrogen ions (H+). Hydrogen ions are hydrogen atoms that have lost an electron and now have just a proton, giving them a positive electrical charge. Bases, on the other hand, mixed with water yield hydroxide ions (OH-).

Answer:

7.505

×

10

22

 atoms. (rounded to third place of decimal)

Explanation:

Answer: 77.7g

Explanation:Please see attachment for explanation

The correct answer of given question is (4) 77.6 g Fe.

- First, balance the chemical equation:

  [tex]2 FeO + 2 Al \rightarrow 2 Fe + Al_2O_3[/tex]

- Calculate the molar masses:

 - FeO: 55.85 (Fe) + 16.00 (O) = 71.85 g/mol

 - Al: 26.98 g/mol

 - Fe: 55.85 g/mol

- Find the limiting reactant:

 - Moles of FeO = Mass of FeO / Molar mass of FeO = 25.0 g / 71.85 g/mol = 0.348 moles

 - Moles of Al = Mass of Al / Molar mass of Al = 25.0 g / 26.98 g/mol = 0.926 moles

 - From the balanced equation, 1 mole of FeO produces 1 mole of Fe, and 2 moles of Al are needed to react with 2 moles of FeO.

 - The limiting reactant is FeO because it produces fewer moles of product compared to Al.

- Calculate the moles of Fe produced:

 - Since FeO is the limiting reactant, the moles of Fe produced are equal to the moles of FeO, which is 0.348 moles.

- Convert moles of Fe to grams:

 - Mass of Fe = Moles of Fe × Molar mass of Fe = 0.348 moles × 55.85 g/mol = 19.44 g

Complete Question:

When 25.0 grams of FeO react with 25.0 grams of Al, how many grams of Fe can be produced?

1) 25.9 g Fe

2) 38.7 g Fe

3) 50.9 g Fe

4) 77.6 g Fe

Answer:

D

Explanation:

We in same class

Matter are anything that is made up of atoms. The quantity of matter can be observed only on the basis of mass and volume calculation. Therefore, the correct option is option A.

Matter is a substance that has some mass and can occupy some volume. The matter is mainly used in science. Matter can be solid, liquid or gas.

Matter is anything that is made up of atoms. Anything around us that can be physically seen and touched are matter. Ice, water and water vapors are example of matter.

So as we saw that matter has some mass so mass can be measured in gram only. Mass can also be represented as number of molecules. We also saw that matter occupy some volume and that volume is measured only in liter. To determine cleavage and fracture, rock hammer is used.

Therefore, the correct option is option A.

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Answer:

Lol what ya in the same class? Like ya see each other everyday wth

Explanation:

Ex: ya really need sum help

In the provided question, Diamond is ranked the highest on Moh's scale with a score of 10. This means that it is the hardest mineral on the scale and is able to scratch all other minerals. Option D is the correct option.

The Moh's scale is a system for measuring the hardness of minerals based on their ability to scratch other materials. The scale ranges from 1 to 10, with 1 being the softest and 10 being the hardest.

Talc is the softest mineral on the Mohs scale, with a score of 1.

Calcite has a score of 3 and quartz has a score of 7.

Diamond is the hardest mineral on the scale, and it is able to scratch all other minerals.

Therefore, option D. Diamond is the correct choice.

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The liquids will arrange themselves in the order; purple, green, red, blue.

Density is defined as the mass per unit volume of a substance. Usually, in a mixture of liquids, the liquid with lower density is found at the top while liquids with higher densities are found below.

In this problem, we know the following;

Density of red liquid -  1.2 grams per centimeter cubed

Density of blue liquid -  1.6 grams per centimeter cubed

Density of green liquid - 0.8 grams per centimeter cubed

Density of purple liquid- 0.1 grams per centimeter cubed

The liquids will therefore arrange themselves in the order; purple, green, red, blue.

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Answer:

C.

Explanation:

Color

Colour is a physical property that requires no tools, scales, or other equipment to determine. So the correct option is C.

It is the aspect of any object that is described by hue, lightness, and saturation. In physical terms, colour is specifically associated with electromagnetic radiation that is of a certain range of wavelengths. This range of wavelengths is visible to the human eye. The radiation of such wavelengths makes up that part of the electromagnetic spectrum that is known as the visible spectrum or light.

In the perception of colour, vision is involved. A person can see even in dim light, however, in that case, a person is not able to differentiate between colours. When more light is present, colours start to appear clearly. Sometimes, the light of a particular critical intensity is also necessary for the perception of colour.

Lastly, the way the response of the brain to the present visual stimuli is also considered. The same object may appear pink to one and green to another. Thus,  the perception of colour is dependent on vision, light, and individual interpretation. It also depends on the understanding of colour which involves physics, physiology, and psychology.

Therefore, the correct option is C.

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Answer:

The range of atoms = (30-300 pm) depending upon the element

Explanation:

The Atomic radii of the atom is the distance from the center of the circle to the outermost orbital.

The center of the circle is the nucleus and the radii is the outermost boundary.

The actual size of the atom is decided on the basis of the Zeff . Also known as effective nuclear charge.

Zeff: It is the net positive charge felt by the outermost electron by the nucleus.

The value of Zeff depends upon the shielding constant. More the shielding less will be the Zeff . Hence the size of the atom increases.

Due to shielding the outermost electrons feel less pull of nucleus.

The greater the Zeff , the smaller the radius of the atom.

The formula used to calculate the atomic mass is :

[tex]r_{n}=\frac{52.9n^{2}}{Z}[/tex]pm

Here "pm"= picometers

[tex]1 pm = 10^{-12}m[/tex]

The size of the smallest atom H-atom = 120 pm

The range of atoms = (30-300 pm)

Isotopic notation of phosphorus-29 is  [tex]_{15} ^{29} P[/tex]

Explanation:

Explanation:

Atomic size

in is defined  as size of on atom or distance from nucleus to outermost shell of an atom.  

 ALONG GROUP -->  it increases.  

For example:- Consider 1st group

Li – 3  2,1    K,L  

Na- 11   2,8,1   K, L, M  

K- 19   2, 8, 8, 1   K,L, M, N  

As we move down the group. , every time a new shell is being added due to which size of an atom increases.  

Along  period - it decreases.  

For example:- consider 3rd period  

Na   Mg   Ar   Si  

2,8,1 2,8,2 2,8,3 2,8,4  

We see every time, a new electron is added to the same shell due to which nuclear charge increases and size decreases.  

That is the reason ,In the above asked question : out of all K is bigger .

Among the given atoms Na, K, Mg, Ca, K (potassium) has the largest atomic radius because it falls furthest down the periodic table, resulting in more electron shells and a larger radius.

The atomic radius of an atom is determined by the number of energy levels that it possesses, which are quantified by the atom's period number on the periodic table. In this case, all four atoms given (Na, K, Mg, Ca) lie in the same period. However, as you move down the periodic table, the atomic radius increases. This is due to the addition of electron shells. Among the given atoms, K (potassium) falls furthest down the periodic table. Therefore, K (potassium) has the largest atomic radius among these four elements.

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There are 0.0747×[tex]10^{23}[/tex] molecules in 0.0124 moles of [tex]C H_{2} O[/tex].

Explanation:

We know that 1 mole of any element is equal to Avagadro's number of molecules present in that element. So in this case, it is stated that 0.0124 moles of [tex]C H_{2} O[/tex] is present. Then the number of molecules will be obtained by multiplying the number of moles with Avagadro's number.

No. of molecules = No.of moles × Avagadro's number

No.of molecules = 0.0124×6.022×[tex]10^{23}[/tex] molecules =0.0747×

Thus, 0.0747×[tex]10^{23}[/tex] molecules of [tex]C H_{2} O[/tex] are present in 0.0124 moles of [tex]C H_{2} O[/tex].

Answer:

Properties that help geologists identify a mineral in a rock are: color, hardness, luster, crystal forms, density, and cleavage. ... Color and density are determined primarily by the chemical composition. Minerals are classified on the basis of their chemical composition.

The chemical properties of a mineral refer to its composition and how it reacts with other substances, such as its solubility in water, acid, or its resistance to heat and electricity.

The chemical properties of a mineral include its composition and how it reacts with other substances. For instance, a mineral's ability to dissolve in acid or its resistance to heat and electricity.

One example of this is Halite (NaCl), a mineral that is soluble in water. It is composed of sodium (Na) and chlorine (Cl) ions

When these ions come into contact with water, they dissolve, which is a chemical property. So, the solubility of Halite in water is a chemical property of this mineral.

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Answer:

3.293 m

Explanation:

Data Given:

Frequency of radio wave = 91.10 FM or 91.10 MHz

1 MHz = 10⁶ Hz

1 Hz = 1 s⁻¹

wavelength = ?

Solution:

As Frequency of radio wave is 91.10 FM or 91.10 MHz

if we look for conversion of MHz to Hz

So,

1 MHz = 10⁶ Hz

91.10 MHz = (91.10)(10⁶)  =  91.1 x 10⁶ Hz

So

91.10 MHz = 91.1 x 10⁶ Hz

Now we look for conversion of Hz to s⁻¹

1 Hz = 1 s⁻¹

91.1 x 10⁶ Hz = 91.1 x 10⁶ s⁻¹

So

91.1 x 10⁶ Hz = 91.1 x 10⁶ s⁻¹

Now equation used to calculate wavelength

         f = c/λ

rearrange the above equation

        λ = c/f ........(1)

Where:

c = speed of light = 3 x 10⁸ ms⁻¹

λ= wavelength

put the values in above equation 1

           λ = 3 x 10⁸ ms⁻¹ / 91.1 x 10⁶ s⁻¹

           λ = 3.293 m

So the wavelength of radio station wave = 3.293 m

The [H+] in the acid rain which has a pH of 5.6 is Hydrogen ion which dissociates from the acidic Carbonic acid.

Explanation:

                              CO₂ + H₂O ----> H₂CO₃

                               H₂CO₃ ----------> [H+] + [HCO₃-]

Using the equation,

              pH = - log [H+] , we can solve for [H+] as following,

                           - pH = log [H+] ,

                             [H+] = 10-pH,

Exponentiating on both sides with base 10. The hydrogen ion concentration is,

[H+] = 10-5.6 = 0.0000025 = 2.51 × 10-6 M.

Answer: tans - 2-pantene

Explanation:

Answer:

north is the word that best completes the sentence

Answer:

It's west.

Explanation:

I picked north and got it wrong. I'm not sure why it's wrong but it is -_-

Answer:

8g

Explanation:

2g of H2 contains 6.02x1023 molecules, therefore, Xg of H2 will contain 2.41x1024 molecules

Xg of H2 = 2x2.41x1024/6.02x1023

The mass of 2.41 x 10²⁴ molecules of hydrogen (H₂) is 8.08 g.

To calculate the mass of 2.41 x 10²⁴ molecules of hydrogen (H₂), we need to follow these steps:

1. Determine the number of moles of H₂ molecules.

2. Calculate the molar mass of H₂.

3. Find the mass of the given quantity of molecules.

Step-by-Step Calculation

1. Determine the number of moles of H₂ molecules:

The number of molecules can be converted to moles using Avogadro's number [tex](6.022 \times 10^{23} \text{ molecules/mol})[/tex].

[tex]\text{Number of moles} = \frac{\text{Number of molecules}}{\text{Avogadro's number}}\\\\\text{Number of moles} = \frac{2.41 \times 10^{24} \text{ molecules}}{6.022 \times 10^{23} \text{ molecules/mol}}\\\\\text{Number of moles} \approx 4.00 \text{ moles}[/tex]

2. Calculate the molar mass of H₂:

The molar mass of a hydrogen atom (H) is approximately 1.01 g/mol. Therefore, the molar mass of H₂ is:

[tex]\text{Molar mass of H}_2 = 2 \times 1.01 \text{ g/mol} = 2.02 \text{ g/mol}[/tex]

3. Find the mass of the given quantity of H₂ molecules:

[tex]\text{Mass} = \text{Number of moles} \times \text{Molar mass} \\\\\text{Mass} = 4.00 \text{ moles} \times 2.02 \text{ g/mol}\\\\\text{Mass} = 8.08 \text{ g}[/tex]

The mass of 2.41 x 10²⁴ molecules of hydrogen (H₂) is 8.08 g.

Answer:

Ba²⁺(aq) + SO₄²⁻(aq)  →   BaSO₄(s)

Explanation:

Chemical equation:

BaCl₂ +  Na₂SO₄   →   BaSO₄ + NaCl

Balanced Chemical equation:

BaCl₂(aq) +  Na₂SO₄(aq)   →   BaSO₄(s) + 2NaCl(aq)

Ionic equation:

Ba²⁺(aq) + 2Cl⁻(aq) + 2Na⁺(aq) + SO₄²⁻(aq)  →  BaSO₄(s)+ 2Na⁺(aq) + 2Cl⁻ (aq)

Net ionic equation:

Ba²⁺(aq) + SO₄²⁻(aq)  →   BaSO₄(s)

The Na⁺ (aq) and Cl⁻(aq) are spectator ions that's why these are not written in net ionic equation. The barium sulfate is present in solid form that's why can not be splitted into ions.

Spectator ions:

These ions are same in both side of chemical reaction. These ions are cancel out. Their presence can not effect the equilibrium of reaction that's why these ions are omitted in net ionic equation.  

Answer:

It increases by a factor of four

Explanation:

Boyle's Law : At constant temperature , the volume of fixed mass of a gas is inversely proportional to its pressure.

pV = K.......(1)

pV = constant

Charles law : The volume of the gas is directly proportional to temperature at constant pressure.

V = KT

or V/T = K = constant ....(2)

Applying equation (1) and (2)

[tex]\frac{PV}{T}=K[/tex]

[tex]\frac{P_{1}V_{1}}{T_{1}}=\frac{P_{2}V_{2}}{T_{2}}[/tex]

According to question ,

T2 = 4 (T1)

V2 = V1

Put the value of T2 and V2 , The P2 can be calculated,

[tex]\frac{P_{1}V_{1}}{T_{1}}=\frac{P_{2}V_{1}}{4T_{1}}[/tex]

V1 and V1 cancel each other

T1 and T1 cancel each other

We get,

[tex]P1=\frac{P2}{4}[/tex]

or

P2 = 4 P1

So pressure increased by the factor of four

Answer:

b

Explanation:

on edge

Answer:

Components of air, like carbon dioxide, can be considered pollutants when human activity causes their concentration to be larger than normal. At higher concentrations, naturally occurring gases can have undesirable consequences on the environment. High levels of carbon dioxide can cause an increase in Earth’s temperature.

The naturally occurring components of the air become when the level of any component rises above the normal level. Therefore, carbon dioxide can be a pollutant if its concentration rises too much.

Air pollutants can be described as substances in the air that could present at high concentrations, and harm human beings, vegetation, animals, or material.

Air pollutants include types of matter of any natural or artificial components capable of being airborne. Air pollution can be any physical, chemical, or biological change in the air. Air pollution can be described as the contamination of air by harmful gases, smoke, and dust.

In the atmosphere of the earth, there is a certain percentage or range of gases. Any increase or decrease in the concentration of these gases can be harmful to survival. This imbalance in the gases can result in an increase in the earth’s temperature known as global warming.

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Answer:

₉₂U²³⁸   →   ₉₀Th²³⁴  + ₂He⁴  

Explanation:

Alpha beta and gamma radiations are the examples of ionizing radiations. When an atom is an excited state and having high energy, the atom is in unstable state. The excess of energy is released by the atom to get the stability. The released energy is in the form of radiations which may include alpha, beta, gamma, X-ray etc.

Alpha decay:

Alpha radiations are emitted as a result of radioactive decay. The atom emit the alpha particles consist of two proton and two neutrons. Which is also called helium nuclei. When atom undergoes the alpha emission the original atom convert into the atom having mass number less than 4  and atomic number less than 2 as compared to parent atom the starting atom.

Properties of alpha radiation:

Alpha radiations can travel in a short distance.

These radiations can not penetrate into the skin or clothes.

These radiations can be harmful for the human if these are inhaled.

These radiations can be stopped by a piece of paper.

₉₂U²³⁸   →   ₉₀Th²³⁴  + ₂He⁴