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Q8. Na2CO3 Na2O + CO2

is this combustion, synthesis, single replacement, double replacement, or decomposition ?

Answer:

D. 4

Explanation:

Reflection can be defined as a phenomenon which typically involves a change in the direction of a ray of light or waves as it falls on a smooth surface.

Simply stated, reflection occurs when a ray of light or wavefronts bounces off a smooth surface.

Hence, from the diagram provided above, the thin beam of light which illustrates reflection is the fourth because as it hit the surface, it bounced back to the medium from which it was originally propagated with.

Answer:

There are 1.0 * 10^9 seconds in 32 years.

Explanation:

To solve this problem, we will use dimensional analysis, or multiplying by fractions equivalent to 1.

We are starting with a value in years. Since we know that there are 365 days in 1 year, we can multiply the given value (in years) by 365 days/1 year to cancel out the units of years and convert to days:

32 years * 365 days/1 year = 11,680 days

Next, we can use the same idea to convert from days to hours:

11,680 days * 24 hours/1 day = 280,320 hours

And then again for hours to minutes and minutes to seconds:

280,320 hours * 60 minutes/1 hour * 60 seconds/1 minute

= 1009152000 seconds

This answer is quite large, so we will convert to scientific notation to make the value more manageable.

1009152000 seconds = 1.0 * 10^9 seconds

Therefore your answer is 1.0 * 10^9 seconds.

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When omitting the sodium thiosulfate solution from the kinetic trials, the resultant solution from mixing solutions A and B will appear differently than a correctly completed experiment.

Without the sodium thiosulfate, a reaction between the two solutions would not occur, so the resultant solution would be that of an unmixed combination of A and B, rather than a reaction product.

This can be confirmed by running the experiment correctly and including the sodium thiosulfate solution in the kinetic trials.

Omitting the sodium thiosulfate solution can significantly affect the appearance of the resulting solution from a kinetic experiment by not neutralizing the excess iodine and leaving unreacted iodine present in the solution.

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Gravity, as a fundamental force of nature, is influenced by several factors. The following are some of the key factors affecting gravity:

Answer:

The mole and Avogadro’s number are two important concepts of science that provide a link between the properties of individual atoms or molecules and the properties of bulk matter. It is clear that an early theorist of the idea of these two concepts was Avogadro. However, the research literature shows that there is a controversy about the subjects of when and by whom the mole concept was first introduced into science and when and by whom Avogadro’s number was first calculated. Based on this point, the following five matters are taken into consideration in this paper. First, in order to base the subject matter on a strong ground, the historical development of understanding the particulate nature of matter is presented. Second, in 1811, Amedeo Avogadro built the theoretical foundations of the mole concept and the number 6.022 × 1023 mol−1. Third, in 1865, Johann Josef Loschmidt first estimated the number of molecules in a cubic centimetre of a gas under normal conditions as 1.83 × 1018. Fourth, in 1881, August Horstmann first introduced the concept of gram-molecular weight in the sense of today’s mole concept into chemistry and, in 1900, Wilhelm Ostwald first used the term mole instead of the term ‘gram-molecular weight’. Lastly, in 1889, Károly Than first determined the gram-molecular volume of gases under normal conditions as 22,330 cm3. Accordingly, the first value for Avogadro’s number in science history should be 4.09 × 1022 molecules/gram-molecular weight, which is calculated by multiplying Loschmidt’s 1.83 × 1018 molecules/cm3 by Than’s 22,330 cm3/gram-molecular weight. Hence, Avogadro is the originator of the ideas of the mole and the number 6.022 × 1023 mol−1, Horstmann first introduced the mole concept into science/chemistry, and Loschmidt and Than are the scientists who first calculated Avogadro’s number. However, in the science research literature, it is widely expressed that the mole concept was first introduced into chemistry by Ostwald in 1900 and that Avogadro’s number was first calculated by Jean Baptiste Perrin in 1908. As a result, in this study, it is particularly emphasised that Horstmann first introduced the mole concept into science/chemistry and the first value of Avogadro’s number in the history of science was 4.09 × 1022 molecules/gram-molecular weight and Loschmidt and Than together first calculated this number.

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The farmer noticed that the nitrates (NO3) from his fertilizer are disappearing rapidly from his soil. This could be due to several reasons, including: Leaching, Denitrification, Plant Uptake.

Leaching: This is the process whereby nitrates are washed away from the soil by rainfall or irrigation. When there is heavy rainfall or excessive watering, nitrates can be washed away from the topsoil, leaving the plants without the required nutrients.

Denitrification: This is a process whereby bacteria in the soil break down nitrates into nitrogen gas, which is released into the atmosphere. This process can occur in poorly drained soil, which is waterlogged and lacks sufficient oxygen to support plant growth.

Plant Uptake: Nitrogen is a vital nutrient for plant growth, and plants require it to develop leaves, stems, and roots. When plants absorb the nitrogen from the soil, the nitrates in the soil reduce significantly.In conclusion, several factors could lead to the rapid disappearance of nitrates from the soil. The farmer needs to understand the primary cause of the problem to address it effectively. Leaching, denitrification, and plant uptake are some of the reasons the nitrates could be disappearing rapidly from the soil.

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Answer:

See below ~

Explanation:

Basic oxides

Acidic oxides

We are told that we must assume that the gas behaves as an ideal gas in order to apply the following equation:

Where,

P is the pressure of the gas, 0.9801atm

V is the volume of the gas, 13mL=0.013L

R is a constant, 0.08206 atm-L/mol-K

T is the temperature of the gas, 22°C=295.15K

Now, we will clear the moles of the gas, n and we replace the known data:

now, to have the mass of the gas, we will use the molar mass. In this case, the molar mass of O2=31.999g/mol

The grams of O2 produced in the reaction are 1.7x10^-2 g of O2

Answer:

Because they cannot be separated into more then one type of substance.

Explanation:

Answer:

Elements are made of only one kind of atom. The particles can be a single atom or a molecule made of only one kind of atom. There is no physical change that can separate elements into more than one kind of substance. This makes an element a pure substance.An element is made up of only one type of atom. An element cannot be broken down into a simpler form.

The formulas in a chemical equation represent the different compounds or molecules involved in the reaction. The arrow indicates the direction of the reaction, usually pointing from the reactants to the products.

In a chemical equation, the formulas, arrow, and plus signs convey important information about the chemical reaction taking place. The plus signs indicate that multiple reactants or products are present.

1. Formulas: These represent the chemical compounds involved in the reaction, with each formula showing the elements and their proportions in the compound. The formulas on the left side of the equation are the reactants, and those on the right side are the products.

2. Arrow: The arrow in the equation (→) represents the direction of the reaction, indicating that the reactants on the left side are converted into the products on the right side. It can be read as "yields" or "forms."

3. Plus signs: These denote that two or more reactants or products are involved in the reaction. A plus sign between reactants or products indicates they are separate entities participating in or resulting from the chemical reaction.

In summary, the formulas, arrow, and plus signs in a chemical equation describe the reactants, products, and the process of the chemical reaction taking place.

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250 mL of the gas at standard temperature and pressure (STP) has a mass of 0.700 g. By calculating the number of moles of the gas and dividing the mass by the number of moles, the molar mass can be obtained. The correct molar mass among the given options is 62.7 g/mol (Option A).

To find the molar mass, we need to determine the number of moles of the gas. Given that the volume of the gas is 250 mL (or 0.250 L) and the mass is 0.700 g, we can use the ideal gas law equation: PV = nRT. At STP, the pressure (P) is 1 atmosphere (atm), the volume (V) is 0.250 L, the number of moles (n) is what we need to find, the ideal gas constant (R) is 0.0821 L·atm/(mol·K), and the temperature (T) is 273.15 K. Simplifying the equation, we have: (1 atm)(0.250 L) = n(0.0821 L·atm/(mol·K))(273.15 K) Solving for n, we find that the number of moles is approximately 0.010 mol. To calculate the molar mass, we divide the mass of the gas (0.700 g) by the number of moles (0.010 mol): Molar mass = 0.700 g / 0.010 mol ≈ 70 g/mol. Therefore, none of the given options match the calculated molar mass.

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Answer:

atomic number

Explanation:

atomic number is the number of protons

Answer:

Explanation:

Molarity given = 0.2 mol dm ^ -3

wieght of potassium chloride = 2.98g

molar mass of potassium cloride = 74.5

let us assume vol. of water needed= x

molarity = weight  * 1000 / molar mass * volume

             0.2 = 2.98 * 1000 / 74.5 * x

             0.2  = 2980 / 74.5x

            74.5x = 2980 / 0.2

            74.5 x = 14900

            x = 200

hence, volume required is 200 ml

Potassium is a chemical element with atomic number 19 which means there are 19 protons and 19 electrons in the atomic structure12.

An atom of the most common isotope of potassium has a nucleus composed of 19 protons and 20 neutrons3.

The nucleus of a neutral potassium atom is surrounded by 19 electrons3.

Key words

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Taking into account the definition of calorimetry and latent heat, a heat of 2159.5 J is needed to melt 35 g of iodine.

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Latent heat is defined as the energy required by a quantity of substance to change state.

When this change consists of changing from a solid to a liquid phase, it is called heat of fusion and when the change occurs from a liquid to a gaseous state, it is called heat of vaporization.

The heat Q that is necessary to provide for a mass m of a certain substance to change phase is equal to

Q = m×L

where L is called the latent heat of the substance and depends on the type of phase change.

In this case, you know:

Replacing in the definition of latent heat:

Q= 35 g× 61.7 \(\frac{J}{g}\)

Solving:

Q=2159.5 J

Finally, a heat of 2159.5 J is needed to melt 35 g of iodine.

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75-80 = 5 = .0625 X 100 = 6.25%

80 80

We need 128.04 grams of Al2(SO4)3.18H2O to make 800 mL of a 0.300 M solution. Given that the volume of the solution (V) = 800 mL = 0.8 L

The molarity of the solution (M) = 0.300 M

We have to find out the mass of the compound Al2(SO4)3.18H2O required to make the solution.

To find the mass, we need to use the formula:

mass = molarity x molar mass x volume

Here, the molar mass of Al2(SO4)3.18

H2O = 666.39 g/mol (sum of the atomic weights of Al, S, O, and H)

Let the mass of the compound be x grams. Substituting the given values in the above formula:

mass = 0.300 x 666.39 x 0.8

= 160.05 x 0.8

= 128.04 g

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Explanation:

for more inforamation you shall search

Answer:

The heterogeneous mixture that has very small dispersed particles and stays mixed for a long time is colloid. Because colloid has particles that are small enough to suspended but are as large that they can scatter light.

Answer:

1. heterogeneous

2. colloid

3. suspension

The molarity equation is as follows: Molarity is defined as moles of solute/liters of solution.

You can calculate the number of moles of solute if you know the molarity (concentration) of a solution and the total volume of the solution (be sure it is in liters). Afterward, you might need to convert the solute's moles to grams.

By percent by mass is another way for estimating the solute concentration in a solution. To do this, an equation of the form

The formula for mass percent is (mass of solute/mass of solution) X 100.

Percent by volume is a third technique for estimating the solute concentration in a solution. The formula for this is:

(Volume of Solute/Volume of Solution) X 100% is the formula for percent by volume.

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Answer: Ionic attractions

Explanation:

Ionic bonding is a type of chemical bond that involves the electrostatic attraction between oppositely charged ions.

Approximately 0.09 moles of ammonia (NH3) can be produced from the given conditions.

To determine the number of moles of ammonia (NH3) that can be produced, we need to use the ideal gas law and the balanced chemical equation for the reaction.

The balanced chemical equation for the reaction between hydrogen (H2) and nitrogen (N2) to produce ammonia (NH3) is:

3H2 + N2 -> 2NH3

From the equation, we can see that 3 moles of hydrogen react with 1 mole of nitrogen to produce 2 moles of ammonia.

First, let's convert the given volume of hydrogen to moles using the ideal gas law:

PV = nRT

Where:

P = pressure (in atm)

V = volume (in liters)

n = moles

R = gas constant (0.0821 L·atm/(mol·K))

T = temperature (in Kelvin)

First, we need to convert the temperature from Celsius to Kelvin:

T(K) = T(°C) + 273.15

T(K) = 50.0 + 273.15 = 323.15 K

Using the ideal gas law, we can calculate the number of moles of hydrogen:

n(H2) = PV / RT

n(H2) = (1.2 atm) * (4.0 L) / (0.0821 L·atm/(mol·K) * 323.15 K)

n(H2) ≈ 0.18 moles

Since we have an excess of nitrogen, the amount of nitrogen will not limit the reaction. Therefore, the number of moles of ammonia produced will be half the number of moles of hydrogen:

n(NH3) = 0.5 * n(H2)

n(NH3) ≈ 0.5 * 0.18 moles

n(NH3) ≈ 0.09 moles

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Answer:

H2O

Explanation:

it is composed of 2 atoms of Hidro and 1 atom Oxy

Answer:

The chemical formula for water is H2O..it is composed by the bonding of 2 molecules of hydrogen and one molecule of oxygen,a covalent bond to be specific.

I hope this helps

A characteristic of a base is that it increases the amount of hydroxide ions (OH-) in a solution, not the amount of hydrogen ions (H+). Therefore, the response "increases amount of hydrogen ions" is incorrect.

Bases are indeed slippery to the touch, so the response "is slippery" is a characteristic of a base.

Contrarily, bases often cause the litmus paper to become blue rather than red. To evaluate if a chemical is acidic or basic, people frequently use litmus paper as an indicator. Litmus paper is coloured red by acids and blue by bases. As a result, the answer "turns litmus paper red" is untrue.

Last but not least, bases are known to taste soapy or bitter rather than sour. On the other hand, acids have a sour flavour. As a result, the answer "tastes sour" is untrue.

In conclusion, the accurate definition of a base is a substance that makes a solution contain more hydroxide ions (OH-) and is slippery to the touch.

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The chemist has 642.4 millimoles of barium acetate in the solution.

To calculate the millimoles of barium acetate (Ba(C₂H₃O₂)₂) in the solution, we can use the formula:

moles = molarity × volume (in liters)

First, let's convert the volume from milliliters (mL) to liters (L):

440.0 mL ÷ 1000 = 0.440 L

Now we can substitute the given values into the formula:

moles = 1.46 M × 0.440 L

moles = 0.6424 mol (rounded to 4 decimal places)

To convert the moles to millimoles, we multiply by 1000:

millimoles = 0.6424 mol × 1000

millimoles = 642.4 mmol (rounded to 3 significant digits)

Therefore, the chemist has 642.4 millimoles of barium acetate in the solution.

It's important to note that the molarity (M) represents the number of moles of solute per liter of solution. By multiplying the molarity by the volume in liters, we can find the number of moles of solute. To convert moles to millimoles, we multiply by 1000. The result represents the millimoles of barium acetate present in the given volume of solution.

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The combined effects of social vulnerability, unequal environmental exposure, and biological/physiological susceptibility result in health disparities among racial/ethnic and socioeconomic groups.

When there are social inequalities in the places where people live, work, learn, and play, environmental factors can contribute to disease and health disparities.

These social injustices, also known as social determinants of health, include disparities in people's behaviors, cultural influences, access to healthcare, economic status, and literacy levels. When social injustices and poor environmental quality are present together, communities are said to have environmental health disparities when they experience higher rates of illness and disease than wealthier, less polluted communities.

Environmental hazards and social conditions must be taken into consideration in order to eliminate disparities in environmental health.

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Explanation:

Magnesium - Group 2

Nitrogen - Group 5

The balanced equation for the reaction is given as;

3Mg + N₂ --> Mg₃N₂

Type of reaction;

Synthesis / Direct Combination