Write the balanced chemical equation that represents the standard heat of formation of cro3(s) at 298 k.

Answer:

112g + 64g = 176g

Explanation:

Just pretty much put the things together or add them

The volume of a 75-gram sample of gold at STP is approximately 3.886 cubic centimeters, calculated using the formula V = m/d, where m is the mass and d is the density of gold.

To determine the volume of a 75-gram sample of gold at standard temperature and pressure (STP), we must use the formula that relates mass (m), density (d), and volume (V), which is m = dV. Since the density (d) of gold is 19.3 g/cm³, we can rearrange the formula to solve for volume: V = m/d.

By plugging in the mass of the gold sample and the given density, we get:

V = 75 g / 19.3 g/cm³ = 3.886 cm³

Therefore, the volume of a 75-gram sample of gold at STP is approximately 3.886 cubic centimeters.

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Answer: The density of cone is [tex]0.115g/cm^3[/tex]

Explanation:

The equation used to calculate the volume of cone is:

[tex]V=\frac{1}{3}\pi r^2h[/tex]

where,

V = volume of cone

r = radius of the cone = 5 cm

h = height of the cone = 2 cm

Putting values in above equation, we get:

[tex]V=\frac{1}{3}\times (3.14)\times (5)^2\times 2\\\\V=52.33cm^3[/tex]

To calculate volume of a substance, we use the equation:

[tex]\text{Density of a substance}=\frac{\text{Mass of a substance}}{\text{Volume of a substance}}[/tex]

We are given:

Mass of cone = 6 g

Volume of cone = [tex]52.33cm^3[/tex]

Putting values in above equation, we get:

[tex]\text{Density of cone}=\frac{6g}{52.33cm^3}\\\\\text{Density of cone}=0.115g/cm^3[/tex]

Hence, the density of cone is [tex]0.115g/cm^3[/tex]

For us to accurately determine what compound this is, additional info must be given. However I can suggest two compounds which have molecular mass of about 30.07 g/mol.

1. It could be NO or nitric oxide.

The molecular mass is 16 + 14= 30 g/mol

But if we search the exact weight, it is 30.01 g/mol

2. It could also be (CH3)2  or ethane.

The molecular mass is 2*12+ 6*1= 30 g/mol

But if we search the exact weight, it is 30.07 g/mol.

So we could say it more likely to to be (CH3)2 

Answer:

C2H6

Explanation:

There is no central carbon atom therefore you can put subscripts on both atoms.

Answer: mass = 19 grams

Explanation: Density is directly proportional to mass and indirectly proportional to the volume. So, the density formula is:

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

density and volume are given and the question asks to calculate the mass. So, the formula could be rearranged as:

mass = density x volume

Given density is [tex]\frac{5.2g}{cm^3}[/tex] and the volume is [tex]3.7cm^3[/tex] .

Let's plug in the values in the formula to calculate the mass:

mass = [tex]\frac{5.2g}{cm^3}*3.7cm^3[/tex]

mass = 19.24 grams

Both the density and volume have two sig figs, so if the answer is round off to correct number of sig figs then the mass will be 19 grams.

The distinction between a strong acid (HClO₄) and a weak acid (HClO₂) lies in the extent of ionization in the solution. Strong acids ionize fully, while weak acids only partially ionize.

A strong acid is one that completely ionizes in water, while a weak acid only partially ionizes. The extent to which a substance is ionized in solution is determined by its dissociation constant (Ka).

HClO₄ is considered a strong acid because it fully dissociates into its ions when dissolved in water.

HClO₂ (chlorous acid),  is a weak acid. It only partially ionizes in water, meaning that only a fraction of the HClO₂ molecules dissociate into H+ and ClO⁻² ions. As a result, the concentration of H+ ions in the solution is lower compared to a strong acid like HClO₄, resulting in a weaker acidity.

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To calculate the empirical formula from percent compositions, convert the percent composition of each element to grams, then to moles, and finally, divide the moles by the smallest number of moles obtained. In this case, the empirical formula is C5H7N.

The empirical formula can be calculated by finding the moles of each element in the compound using their percent compositions. In this case, we have 82% nitrogen, which corresponds to 82 grams, and 18% hydrogen, which corresponds to 18 grams. Next, we convert the grams to moles using the molar mass of each element. The molar mass of nitrogen (N) is 14 grams/mol, and the molar mass of hydrogen (H) is 1 gram/mol. Dividing the moles by the smallest number of moles obtained gives us the empirical formula. For this compound, the empirical formula is C5H7N.

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Final answer:

Molarity is a quantitative measure for the concentration of a solution, defined as the number of moles of solute per liter of solution, and is calculated by dividing moles of solute by liters of solution.

Explanation:

The concentration of a solution can be quantitatively expressed using molarity, which is one of the most frequently used methods by chemists. Molarity is defined as the number of moles of solute per liter of solution. To calculate the molarity of a solution, you must first determine the amount of solute in moles and then measure the total volume of the solution in liters. For example, if you have 1.5 moles of NaCl dissolved in 0.500 liters of solution, the molarity (M) of the solution is calculated by dividing the number of moles of solute by the number of liters of solution, resulting in a 3 molar (3 M) solution of NaCl.

Final answer:

The nuclear symbol for the isotope with 26 protons and 30 neutrons is 56 Fe, and the hyphen notation is iron-56 or Fe-56. The element is iron (Fe).

Explanation:

The isotope in question has 26 protons and 30 neutrons. To find the nuclear symbol and the hyphen notation, we need to identify the element and calculate the mass number. This notation represents that the atom is an iron isotope with a mass number of 56 and an atomic number of 26 .

The element with 26 protons is iron (Fe).

The mass number (A) is the sum of the protons and neutrons, so A = 26 + 30 = 56.

Therefore, the nuclear symbol is 56 Fe, where 56 is the mass number and Fe is the symbol for iron.

The hyphen notation for this isotope is iron-56 or Fe-56.

To determine the number of moles of carbon monoxide present in the sample, use the Ideal Gas Law equation.

To determine the number of moles of carbon monoxide present in the sample, we can use the Ideal Gas Law equation, which is PV = nRT, where P is the pressure, V is the volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

First, convert the temperature from Celsius to Kelvin by adding 273.15. So, the temperature is 57°C + 273.15 = 330.15 K.

Now, rearrange the Ideal Gas Law equation to solve for n: n = PV / RT.

Substituting the given values into the equation, we have n = (67.88 kPa) * (85.3 L) / (0.0831 L·kPa/(mol·K)) * (330.15 K).

Simplifying the equation, we have n ≈ 231.36 moles of carbon monoxide in the sample.

The heat of reaction is -79.2 kJ/mol.

The equation of the reaction is;

CaO(s) + 2H2O(l) ------> Ca(OH)2(aq) + H2(g)

Number of moles of CaO =  6.50 g/56 g/mol = 0.12 moles

Number of moles of H2O =  99.70 g/18 g/mol = 5.53 moles

Temperature rise =  43.1 °C -  21.7 °C = 21.4  °C

Total mass of solution = 99.70 g + 6.50 g = 106.2 g

We must obtain the limiting reactant as follows;

1 mole of CaO reacts with 2 moles of H2O

0.12 mole of CaO reacts with 0.12 mole × 2 moles/1 mole = 0.24 moles

We can see that CaO is the limiting reactant.

Heat absorbed = 106.2 g ×  4.18 J/g-1K-1 × 21.4  °C = 9.5 kJ

Heat of reaction = -(9.5 kJ/0.12 moles) = -79.2 kJ/mol

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To determine if a molecule is polar or nonpolar, follow these steps: draw the Lewis structure, figure out the molecular geometry, visualize or draw the geometry, and find the net dipole moment.

To determine if a molecule is polar or nonpolar, you need to follow a few steps:

In the case of CH3SH, the Lewis structure is H-C-H, with an S bonded to the central C atom. The geometry of the molecule is pyramidal, with the S atom at the top and the H atoms forming a triangular base. The S atom has higher electronegativity than the C and H atoms, so the S-H bond will be polar. Taking into account the molecular geometry, CH3SH is a polar molecule.

Answer:

Opinion

Explanation:

This is an opinion, actually. A Hypothesis has an "if/then" statement, for example, "IF I do not tie a knot at the end of a balloon THEN it will deflate". A scientific law states a fact that can be proven, such as Newtons Laws. A problem is the question you ask without making an educated guess.

Hope I helped! :)

A hypertonic solution has a higher osmolarity than a cell's cytoplasm, leading to water exiting the cell, known as crenation in red blood cells and plasmolysis in plant cells.

A hypertonic solution is one where the extracellular fluid has a higher osmolarity than the cytoplasm of a cell, causing water to move out of the cell. In such a solution, cells will lose water and shrink, which can be observed in red blood cells as crenation. Additionally, in plant cells, this phenomenon can result in the cell membrane detaching from the cell wall, known as plasmolysis.

To determine which flask holds which sucrose solution, you can use a method called titration. This involves adding a known solution that does not contain sucrose to each flask and noting when the indicator solution changes color. By comparing the volumes of the known solution required for each flask, you can determine the relative concentrations of the sucrose solutions.

In order to determine which flask holds which solution, we can use a method called titration. Here's how it works:

Answer:

The boron-11 should be more abundant

Explanation:

Atomic weight in the periodic table is an average value related to the percentaje of abundance of each isotope of the element.

Given that boron has only two isotopes (10 and 11), if their abundance would be 50%:

[tex]Ar=10*0.5+11*0.5=10.5[/tex]

Knowing that the boron's Ar is 10.81, we can afirm that boron-11 is more abundant.

Theoretically, boron atomicities of 10 and 11 are 10.5 on average. However, realistically speaking, boron has an atomic mass of 10.81 amu. Thus, it demonstrates that the average atomic mass of boron contains a higher abundance of boron-11. Atomic mass per unit, or amu, is a unit used to measure atomic mass.

If the abundance of boron-10 and boron-11 were equal, boron's atomic mass would be 10.5 amu. Therefore, the atomic mass of boron would be less than 10.5 amu if the percentage abundance of boron-10 is greater than the percentage abundance of boron-11.

In actuality, the atomic mass of boron is 10.81 amu rather than 10.5 amu, indicating that boron-11 has a higher proportion abundance than boron-10.

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Answer: Option (d) is the correct answer.

Explanation:

A hypothesis is referred to as an idea which might be a possible explanation for a particular experiment or situation but it is not necessarily correct.

So, in order to form a hypothesis, a scientist has to theoretically look into the problem so that he can provide or suggest a possible explanation for the same.

This is because when the scientist looks theoretically into a problem then he will check all the steps in detail and its possible outcomes or results. This will lead to a possibility that the suggested hypothesis will be correct.

Answer: The Atom would have:  

9 protons

19 electrons (since atoms are electrically neutral and have the same number of electrons as protons)

20 neutrons

Explanation: Hope this Helps.

Final answer:

The scientist is conducting descriptive research, documenting soil composition changes in a forest over time without manipulating the environment.

Explanation:

The scientist performing an investigation by collecting soil composition data in a forest after a wildfire and analyzing it for trends over ten years is conducting descriptive research. This type of investigation involves documenting and describing changes in the environment without manipulating any variables. Descriptive research aims to accurately portray the characteristics of a particular individual, situation, or group over time and is foundational in natural sciences, including soil science and ecology.

In contrast to experimental research, which involves creating a controlled environment to test specific hypotheses, descriptive research documents real-world phenomena as they naturally occur. Moreover, this type of research is crucial for understanding ecological succession, how ecosystems recover after disturbances, and for guiding conservation and management practices.