The tip of a match is ignited as it is struck against the matchbox. Why is this a chemical change?

The color of the match tip has changed.
The match changes size as it burns.
The tip of the match is flammable and is set on fire.
The match is melting.

Answer:

51.996 amu  

B) 52.000 amu  

C) 52.191 amu  

D) 52.25 amu

Explanation:

Which one would it be on here?

Explanation:

According to the ideal gas law, PV = nRT

where, n = number of moles

Also, density = [tex]\frac{mass}{volume}[/tex]

Since,   n = [tex]\frac{mass}{\molar mass}[/tex]

Therefore, ideal gas equation can also be written as follows.

                  PV = nRT

                  PV = [tex]\frac{mass}{\text{molar mass}} \times RT[/tex]

         [tex]P \times \text{molar mass}[/tex] = dRT

Hence, putting the given values into the above formula as follows.

           [tex]0.874 atm \times 70.49 g/mol = d \times 0.0821 Latm/mol K \times 389 K[/tex]

                      6.161 atm g/mol = [tex]d \times 31.94 Latm/mol[/tex]

                             d = 0.193 g/L

Thus, we can conclude that density of the given gas is 0.193 g/L.

The density of a gas with a molar mass of 70.49 g/mol at 0.874 atm and 389 K is calculated using the Ideal Gas Law and is approximately 1.928 g/L.

To calculate the density of a gas with a molar mass of 70.49 g/mol at 0.874 atm and 389 K, we can use the Ideal Gas Law, which states PV = nRT. Here, density (d) is equivalent to the mass (m) of the gas divided by its volume (V), and the number of moles (n) can be found by dividing the mass (m) by the molar mass (M). We then rearrange the Ideal Gas Law to solve for n/V, which gives us the formula for density (d = PM/RT).

Using the provided gas conditions and the Ideal Gas constant (R = 0.0821 L·atm/mol·K), we can perform the following calculation:

First, convert the pressure from atm to the unit matching the gas constant: P = 0.874 atm.

Now, insert all values into the density formula: d = (P × M) / (R × T) = (0.874 atm × 70.49 g/mol) / (0.0821 L·atm/mol·K × 389 K).

Perform the multiplication and division to find the density: d ≈ (61.60826 g·atm/mol·K) / (31.9589 L·atm/mol·K) ≈ 1.928 g/L.

Answer:

In biology, adaptation has three related meanings. The definition that relates most to this question is given below:

Adaptation is the dynamic evolutionary process that fits organisms to their environment, enhancing their evolutionary fitness.

A Nettle plant also known as common nettle, stinging nettle nettle leaf, or just a nettle or stinger, is a herbaceous perennial flowering plant in the family Urticaceae with the ability to sting.

Explanation:

One of the biological traits that the nettle has is its ability to produce inflammatory effect (that is a burning stinging sensation on the skin known as "contact urticaria"). This unpleasant effect is achieved by impaling the skin of the animal via spicules. The spicules cause mechanical irritation.

The stinging effect is also achieved by the introduction of biochemical irritants such as histamine, serotonin and choline among other chemicals into the skin.

This sort of defence or protection mechanisam keeps animals away from the nettle.

Cheers!

Blizzards pose hazards beyond hurricane-force winds and snow-filled roads, including infrastructure failures leading to fatalities, potential health issues like respiratory ailments, injuries due to hazardous conditions, and significant economic impacts.

Beyond the direct impact of hurricane-force winds and snow-filled roads, blizzards can cause various other hazards that affect both people and the environment. Critical infrastructure can fail, as seen in the south Texas freeze, where electrical capacity faltered leading to widespread blackouts. The lack of power in freezing temperatures can lead to fatalities and other severe consequences, including the inability to heat homes, frozen and burst water pipes, and the loss or contamination of the water supply.

Another major hazard caused by blizzards is the health impact on individuals. This includes conditions like 'dust pneumonia,' especially among those vulnerable such as children and the elderly, due to prolonged exposure to dust and soot inhalation. In addition, extreme weather conditions can lead to a higher incidence of injuries and exacerbate chronic health conditions, including respiratory diseases. Moreover, the economic damage from such a storm can be immense, disrupting local economies and livelihoods long after the storm has passed.

Final answer:

Potassium (K) is an example of an element whose valence electrons feel a smaller effective nuclear charge than the valence electrons of a calcium (Ca) atom due to potassium's lower number of protons in the nucleus and similar shielding effect.

Explanation:

The concept of effective nuclear charge (Zeff) is important to understand why valence electrons in some elements feel a weaker nuclear pull compared to calcium (Ca). Effective nuclear charge essentially means the net positive charge experienced by valence electrons, after accounting for the shielding effect of the inner electrons. Calcium is a Group 2 element with a 4s2 valence electron configuration. A good example of an element whose valence electrons would feel a smaller effective nuclear charge than those of calcium would be potassium (K).

Potassium, being in the same period but belonging to Group 1, has one valence electron in its 4s orbital. Due to the lower nuclear charge (less protons in the nucleus) and similar shielding by inner electrons, potassium's single valence electron feels less pull from its nucleus compared to a calcium's two valence electrons. Moreover, when potassium forms a cation by losing its valence electron, the remaining electrons are still shielded by the same number of inner electrons, but now there is one less proton in the nucleus to exert a pull. Consequently, the valence electron in a potassium atom would experience a lower effective nuclear charge compared to the valence electrons in a calcium atom.

Answer: Size of Solute and Surface area

Explanation:  Rate of dissolution is the speed at which the given solute gets dissolved in the given solvent.

Now this rate of dissolution depends on may factors like-

a) Size of Solute - If the solute size is bigger then it will take much more time to get dissolved. Thus smaller size solute are easily dissolved in the solvent.

b)  Surface area - If the surface area of the solvent is larger, then the collision between the solute and solvent will be much higher and thus rate of dissolution will increase.

Thus decreasing the surface area of solute will lead to decrease in the rate of dissolution.

Answer:

Significant figures: 2

Explanation:

There are 2 significant figures since the zeros at the left side don’t count and the number can be expressed in its scientific notation as 11x10-3 cm

Dalton's atomic theory proposed that elements are made of atoms, which are indivisible and have specific mass and properties for each element. His theory also stated that atoms combine in fixed ratios to form compounds and cannot be created or destroyed in chemical reactions. Modifications have been made to this theory, as atoms can be divided and isotopes and nuclear reactions exist.

Dalton's Atomic Theory

John Dalton's atomic theory was a groundbreaking attempt to explain the nature and behavior of atoms. The main points of Dalton's atomic theory include:

Elements are composed of extremely small particles called atoms.

Atoms of a given element are identical in size, mass, and other properties; atoms of different elements differ in these properties.

Atoms cannot be subdivided, created, or destroyed in chemical reactions.

Atoms of different elements can combine in whole number ratios to form chemical compounds.

In chemical reactions, atoms are rearranged, combined, or separated.

Despite its success, modifications to Dalton's atomic theory have been made. We now know that atoms can be divided into subatomic particles (electrons, protons, and neutrons), isotopes of elements can have different masses, and atoms can be transformed via nuclear reactions.

Answer: Mineral's streak tells us about the color of the mineral when crushed into powdered form.

Explanation:

Mineral's Streak : Streak of a mineral is a color of a mineral in powdered form. sometimes color of the powder differ from the color of the mineral's specimen.

This test is performed by rubbing a mineral on a un-glazed porcelain tile known as streak plate. By rubbing the mineral on streak plate small amount powder is produced on the surface of the which color can be easily seen with help of eyes.

Answer: Silver nitrate is the chemical reagent used to distinguish.

Explanation:

Dissolve both compounds in water. And add silver nitrate to that solution.

1. In case of calcium chloride

The calcium chloride is soluble in water and thus forms ions in aqueous solution.The chloride ions present in the solution react with silver ions of silver nitrate to give white color precipitate of silver chloride.

[tex]2AgNO_3+CaCl_2\rightarrow 2AgCl(white)+Ca(NO_3)_2[/tex]

2. in case of calcium carbonate.

The calcium carbonate is poorly soluble in water. Since, it doesn't get dissolved in water.

When silver nitrate is added there will be no formation of any precipitate.

Answer:

41,160 is the first

4,200 is the second

less than is the third

6,860 is the last one

Explanation:

The weight of the Lunar Landing module on Earth is 41202 N

The mass of the lunar landing module on the moon is 4200 N

The weight of the lunar landing module on the moon is less than its weight on Earth.

The calculated weight in the moon is 6867 N

A lunar landing module is a lunar landing designed to enable astronauts to travel via a spacecraft in a lunar orbit as well as the lunar surface.

From the given  parameters:

The weight of the Lunar Landing module on Earth is:

Weight on Earth = mass (m) × acceleration due to gravity (g)

Weight on Earth = 4200 kg × 9.81 m/s²

Weight on Earth = 41202 N

The mass of the Lunar Landing module on the Moon is calculated by using the formula:

Weight on Moon = mass (m) × acceleration in the moon

Where;

Since mass on earth = mass in the moon;

The weight of the lunar landing module on the moon is less than its weight on Earth.

The calculated weight in moon = 4200 × 1.635 m/s²

The weight in moon = 6867 N

Learn more about Lunar Landing Module here:

https://brainly.com/question/13633842

Answer :  The correct option is, (B) Gallons

Explanation :

English system : It is defined as the measurement system that is used in many countries including the United States.

The English system measured the things in feet, inches and mile for length, ounce, ton, pint and gallons for volume.

As per question, we conclude that  the unit of volume in the English system of measurement is gallons.

Hence, the correct option is (B) Gallons

The volume of the substance can be calculated by dividing the given mass (0.451g) by the density (0.824 g/mL). Therefore, the volume equals approximately 0.547 mL.

The subject of this question is the calculation of volume using the given mass and density of a substance. The density is defined as mass per unit volume. Thus, you can calculate volume by dividing the mass by the density.

For this specific question, the given mass of the substance is 0.451g and the density is 0.824 g/mL. To calculate volume, divide the mass by the density. So, Volume = mass/density = 0.451g / 0.824 g/mL = 0.547 mL.

https://brainly.com/question/33318354

#SPJ12

For pure substances, the mass and volume will always be the same or will always change the same way because all substance are the same throughout.

While for mixtures, you can have varying amount of each component therefore mass and volume will not change the same way for substances.

[tex]\text{Hey there!}[/tex]

[tex]\text{Vanessa jogged 8 miles in 2 hours. What was her average speed?}[/tex]

[tex]\text{First,, highlight/ underline your key-terms. Then solve it from there!}[/tex]

[tex]\text{Key term  1: \underline{8 miles}}\\\text{Key term 2: \underline{ in 2 hours}}[/tex]

[tex]\text{Now we have to find her average speed. }[/tex]

[tex]\text{Formula: }\dfrac{\text{a}}{\text{b}}[/tex]

[tex]\text{a = 8}\\\text{b = 2}[/tex]

[tex]\dfrac{8}{2}= \text{the answer}\\\\\dfrac{8\div2}{2\div2}=\dfrac{4}{1}= 4\\\\\\\boxed{\boxed{\bf{Answer: 4}}}\checkmark[/tex]

[tex]\text{Good luck on your assignment and enjoy your day!}\\\\\frak{LoveYourselfFirst:)}[/tex]

Answer: 4.3020 grams of calcium sulfate will be produced.

Explanation:

To calculate the number of moles, we use the formula:

[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]    ....(1)

Given mass of calcium carbonate = 3.1660 g

Molar mass of calcium carbonate = 100.0869 g/mol

Putting values in above equation, we get:

[tex]\text{Moles of calcium carbonate}=\frac{3.1660g}{100.0869g/mol}=0.0316mol[/tex]

Given mass of sulfuric acid = 3.2900 g

Molar mass of sulfuric acid = 98.079 g/mol

Putting values in above equation, we get:

[tex]\text{Moles of sulfuric acid}=\frac{3.2900g}{98.079g/mol}=0.0335mol[/tex]

For the given reaction:

[tex]CaCO_3+H_2SO_4\rightarrow CaSO_4+H_2CO_3[/tex]

By Stoichiometry of the reaction:

1 mole of calcium carbonate reacts with 1 mole of sulfuric acid

So, 0.0316 moles of calcium carbonate will react with = [tex]\frac{1}{1}\times 0.0316mol=0.0316mol[/tex]

As, the given amount of sulfuric acid is more than the required amount. Hence, it is present in excess and is considered as an excess reagent.

Calcium carbonate is considered as a limiting reagent because it limits the formation of product.

1 mole of calcium carbonate produces 1 mole of calcium sulfate

So, 0.0316 moles of calcium carbonate will produce = [tex]\frac{1}{1}\times 0.0316mol=0.0316mol[/tex] of calcium sulfate.

Now, to calculate the mass of calcium sulfate, we use equation 1:

Molar mass of calcium sulfate = 136.14 g/mol

Moles of calcium sulfate = 0.0316mol

Putting values in equation 1, we get:

[tex]0.0316mol=\frac{Mass of calcium sulfate}}{136.14g/mol}\\\\\text{Mass of calcium sulfate}=4.3020g[/tex]

Hence, 4.3020 grams of calcium sulfate will be produced.

Final answer:

The coefficient that should be placed in front of H2O to balance the hydrogen atoms for the combustion of ethanol is 3. After balancing the hydrogen atoms, the fully balanced chemical equation for the combustion of ethanol is C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l).

Explanation:

To balance the hydrogen atoms in the combustion of ethanol, we start with the unbalanced equation C2H5OH(l) + O2(g) → CO2(g) + H2O(l). Ethanol (C2H5OH) contains 6 hydrogen atoms, and since each molecule of water (H2O) contains 2 hydrogen atoms, we need 3 molecules of water to account for all the hydrogen atoms from ethanol. Therefore, the coefficient for H2O in the balanced equation is 3.

After placing 3 in front of H2O, the equation looks like this: C2H5OH(l) + O2(g) → 2CO2(g) + 3H2O(l), which balances the hydrogen atoms. To complete the balancing, the oxygen atoms also need to be accounted for. In the product side, there are a total of 7 oxygen atoms (4 from the 2CO2 and 3 from the 3H2O). There is 1 oxygen atom in the ethanol molecule, so we need 6 more oxygen atoms from O2, which means we need 3 O2 molecules. Thus, the coefficient for O2 is 3. The fully balanced equation is C2H5OH(l) + 3O2(g) → 2CO2(g) + 3H2O(l).