PLS HELP ME WITH THIS QUESTION answer all blanks

Answer:

2,7

Explanation:

Two in the first shell and 7 in the outer and last shell.

HOPE THIS HELPED

Answer:

Question: What is heat?

Answer: Heat is a form of energy It can be transferred but not destroyed and is the energy that flows from a hotter object to a less hot to a cold one due to a temperature difference between the objects, meaning an object would continually be cold unless it acquires heat from a hot object or source through heat transfer mechanisms which can be conduction, convection, or radiation, and it is measured usually in calories or joules.

Question: In which direction does heat flow?

Answer: Heat practically flows from a hot object which has a higher temperature to a cold object which temperature is lower through conduction, convection, radiation.

Question: What does thermochemistry involve?

Answer: Thermochemistry is the study of heat as a form of energy making it possible to determine the relationship between heat and chemical reactions which is necessary to know if a reaction would take place or not.

Question: How do we measure heat?

Answer: it is measured usually in calories or joules using thermometers and pyrometers.

Answer:

The primary reason why cars in Mombasa rust faster than those in Nairobi is because the humidity ( water evaporation rate) in Mombasa is higher than that of Nairobi. Since Mombasa has higher temperatures the rate of water evaporation is higher which results into a higer humidity.

Explanation:

This is why cars in Mombasa rust faster than those in Nairobi

Remove dry chemicals.Remove contaminated clothing or jewelry. Bandage the burn. Rinse again if needed.

the amount of harm to the skin relies upon on how strong the chemical was, how lots of it become at the skin, and how long it become there. Chemical burns, even minor ones, can be very painful. A minor burn may heal inside a few days. however a extra extreme burn might also take weeks or maybe months to heal completely.you need to now not use ice, or even ice-bloodless water, on a burn. extreme cold carried out to a burn can further damage the tissue. to properly cool and clean a burn, remove any apparel that covers it.

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Taking into account the reaction stoichiometry, 40 grams of O₂ are needed to react with 0.50 moles of C₂H₂.

In first place, the balanced reaction is:

2 C₂H₂ + 5 O₂ → 4 CO₂ + 2 H₂O

By reaction stoichiometry (that is, the relationship between the amount of reagents and products in a chemical reaction), the following amounts of moles of each compound participate in the reaction:

The molar mass of the compounds is:

Then, by reaction stoichiometry, the following mass quantities of each compound participate in the reaction:

The following rule of three can be applied: if by stoichiometry of the reaction 2 moles of C₂H₂ react with 160 grams of O₂, 0.50 moles of C₂H₂ react with how much mass of O₂?

[tex]mass of O_{2} =\frac{0.50 moles of C_{2} H_{2}x160 grams of O_{2} }{2 moles of C_{2} H_{2}}[/tex]

mass of O₂= 40 grams

Finally, 40 grams of O₂ are needed to react with 0.50 moles of C₂H₂.

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Iron has a BCC crystal structure, an atomic radius of 0. 124 nm, and an atomic weight of 55. 85 g/mol. its theoretical density is 7.9 g /cm³.

The molar mass of the iron = 55.85 g/mol

The atomic radius = 0.124 nm

the edge length is given as :

a = (4r) / √3

a = ( 4 × 0.124 × 10⁻⁷ cm ) / √3

a = 2.86 × 10⁻⁸ cm

The density is given below :

density = ( Z × M ) / Na × a³

density = ( 2 × 55.85 ) / (6.023 ×10²³) × ( 2.86 × 10⁻⁸ )

density = 7.9 g/cm³

Thus the theoretical density is 7.9 g/cm³.

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B) Rubidium is a highly reactive element.

Rubidium is a highly reactive element due to its low ionization energy, which makes it easily lose electrons and form compounds. It is considered to be one of the most reactive alkali metals.

When it comes into contact with water or air making rubidium is highly flammable. It can ignite spontaneously in the air and reacts violently with water to produce rubidium hydroxide and hydrogen gas.

Being noticeably more reactive than potassium but less so than cesium, it is likely to react with substances that are dangerous with sodium or potassium more forcefully. When rubidium is exposed to air or dry oxygen, it ignites, mostly generating oxide.

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To determine the pressure of a gas, we need to use the ideal gas law, which states that PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the ideal gas constant, and T is the temperature in Kelvin.

We can re-arrange the ideal gas law to solve for pressure:

P = (nRT) / V

We are given that the density of the gas is 3.10 g/L, which we can use to calculate the volume of the gas. Density is defined as mass/volume, so we can rearrange the equation to find volume:

V = mass/density

We know the density is 3.10 g/L, and the mass is n * molar mass of N2O.

Molar mass of N2O = (14.01 + 2 * 16.00) g/mol = 44.01 g/mol

The volume of the gas is:

V = mass / density = n * molar mass of N2O / 3.10 g/L

Now we have all the information needed to use the ideal gas law to determine the pressure of the gas.

We are given that the temperature of the gas is 298K.

We can use the ideal gas constant R = 0.0821 Latm/molK

Plugging in the known values:

P = (nRT) / V = (n * 0.0821 Latm/molK * 298K) / (n * molar mass of N2O / 3.10 g/L)

P = (0.0821 * 298) / (44.01 / 3.10) atm

To convert the pressure in atm to mmHg, we need to multiply the pressure by 760 (1 atm = 760 mmHg)

P = (0.0821 * 298) / (44.01 / 3.10) * 760 mmHg

The pressure of the N2O gas is approximately 739.07 mmHg at 298K and density of 3.10 g/L.

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you need 3.00 mL of the 4.00 M sulfuric acid solution to make 12.0 mL of a 0.50 M solution.

Solution is a way to solve a problem or address an issue. It can involve finding an answer or coming up with a strategy to tackle a difficult situation. Solutions can be found through research, brainstorming, trial and error, or by using existing resources.

To solve this problem, we must use the equation:
V1C1 = V2C2
Where V1 is the volume of the concentrated solution, C1 is the concentration of the concentrated solution, V2 is the volume of the dilute solution, and C2 is the concentration of the dilute solution.
In this case, V1 is the volume of the 4.00 M solution that we need, C1 is 4.00 M, V2 is 12.0 mL, and C2 is 0.50 M.
Plugging these values into the equation, we can solve for V1:
V1 = (V2C2) / C1
V1 = (12.0 mL)(0.50 M) / (4.00 M)
V1 = 3.00 mL

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Answer:

Skeleton equation: H2S(g) + O2(g) → SO2(g) + H2O(l)

Explanation:

Answer:

The earth would absorb more sun and temperatures would be a lot higher.

Explanation:

The process orcas uses the oxygen is from the blowholes. the blow holes are situated on the top of of the head and it uses oxygen from their.

The whales and the humans uses the lungs for the respiration or to get oxygen required for the breathing. the orcas uses the oxygen from the blow holes situated at the top of the head. The orcas lives under the water and when the orcas dive in the water they have ability to hold the breath for at the time . but this is not good for the health . it is be very stressful for the body.

Thus, the process do the orcas uses oxygen for the intake is the from the blow holes.

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Explanation:

Causes of climate change are:

1.)Smoke from Vehicles and industrial activities

2.) Burning of polythenes.

3.) Because of green house effect

Effects are:

1.) Extinction of birds,plants and animals

2.) Melting of glaciers

3.) Rise in global temperature

Answer:

Neptune to be precise

Explanation:

cause it is the last planet in our solar system

The compound is Glucose.

C: 40 g divided by 12 g per mol equals 3.333 mol

H: 6.72 g/mol (1 g) = 6.72 mol

O: 53.28 g/mol (16 g) = 3.33 mol

Subtract the lesser amount of moles.

C: 3.333 / 3.33 = 1.00

H: 6.72 / 3.33 = 2.02 ≈ 2

O: 3.33/3.33 = 1.00

Statistical method

The empirical formula's molar mass is 12 g/mol + 2*1 g/mol + 16 g/mol = 30 g/,ol.

180 g/mol / 30 g/mol = 6 times the mass of the empirical formula is contained in the molar mass.

The empirical formula of compound is six times the molecular formula.

=>[tex]C_{6} H_{12} O_{6}[/tex]

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Answer:No of moles of potassium sulfide (K2S)=0.61671moles

Explanation:

No of moles is given as   Mass/ molar mass

Here Mass of potassium sulfide (K2S) =68 grams

Molar mass of potassium sulfide (K2S)  = 39.0983 x 2 + 32.065 =110.2616 g/mol

No of moles =68 grams /110.2616 g/mol

=0.61671moles

The appropriate explanation for the non-metal is that the higher effective nuclear charge less will be the atomic radius.

Atomic radius typically decreases during a period from left to right. There are a few little outliers, such how the oxygen radius is a tiny bit bigger than the nitrogen radius. Protons are gradually added to the nucleus at the same time that electrons are gradually added to the main energy level. The enhanced positive charge of the nucleus gradually attracts these electrons closer to it. The size of the atoms shrinks as the strength of attraction between nuclei and electrons grows. Due to electron-electron repulsions that would otherwise result in the atom's size expanding, the effect becomes less pronounced as one proceeds further to the right in a period.

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Answer:

Explanation:

The number of molecules can be found by using the formula

N = n × L

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

We have

N = 5.4 × 6.02 × 10²³

We have the final answer as

Hope this helps you

Answer: The volume of 0.640 grams of [tex]O_{2}[/tex] gas at Standard Temperature and Pressure (STP) is 0.449 L.

Explanation:

Given: Mass of [tex]O_{2}[/tex] gas = 0.640 g

Pressure = 1.0 atm

Temperature = 273 K

As number of moles is the mass of substance divided by its molar mass.

So, moles of [tex]O_{2}[/tex] (molar mass = 32.0 g/mol) is as follows.

[tex]No. of moles = \frac{mass}{molar mass}\\= \frac{0.640 g}{32.0 g/mol}\\= 0.02 mol[/tex]

Now, ideal gas equation is used to calculate the volume as follows.

PV = nRT

where,

P = pressure

V = volume

n = no. of moles

R = gas constant = 0.0821 L atm/mol K

T = temperature

Substitute the values into above formula as follows.

[tex]PV = nRT\\1.0 atm \times V = 0.02 mol \times 0.0821 L atm/mol K \times 273 K\\V = 0.449 L[/tex]

Thus, we can conclude that the volume of 0.640 grams of [tex]O_{2}[/tex] gas at Standard Temperature and Pressure (STP) is 0.449 L.

Answer:

D

Explanation:

A weak acid and a strong base will form a basic salt.

Option A is acidic, this pH would be found in salts formed from reactions between strong acids and weak bases.

B and C are neutral or close to neutral and as such will be formed from weak acids and weak bases, or strong acids and strong bases.

Answer:

Yea what they said^

Explanation:

Option 4 or D is correct

8.7 is your answer

MARK THE OTHER PERSON BRAINLIEST!!!

Answer:

13.6 g

Explanation:

The mass of BeF₂ present in 655 ml of a solution that is 0.442 M is equal to 13.82 g.

We can calculate the concentration of a solute in a solution in terms of molarity, molality, and normality.

The molarity of a particular solution can be determined from the number of moles of a solute per unit volume of the solution.

The Molarity of the particular solution can be determined from the mathematical formula mentioned below:

Molarity = Moles/Volume of the Solution

Given, the molarity of BeF₂ solution = 0.442 M

The volume of the BeF₂ solution, V = 655 ml = 0.655 L

The molar mass of the BeF₂, M = 47.01 g/mol

Molarity of BeF₂ solution = m/(M × V)

0.442 = m/ (47.01 × 0.655)

m = 13.82 g

Therefore, 13.82 g of BeF₂ is required for the given solution.

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Corrosion is the process of chemical or electrochemical attack of materials by their external environment.

The tendency/resistance of different metals to corrosion largely depends on the composition of the metal. Iron and steel corrode in the presence of oxygen due to oxidation, while some metals such as chromium, nickel and molybdenum provide a protective layer of oxide film on the surface of the metal which is then resistant to corrosion. Other metals such as aluminum and zinc form sacrificial oxide layers which corrode and protect the metal from becoming completely damaged.

The two quantities in this module for which we will develop unit factors to do dimensional analysis with chemical substances are mass (usually measured in grams) and volume (usually measured in liters).

Unit factors are developed to convert between two different units of measurement, in this case, mass and volume. We can do this by multiplying the given value by the appropriate unit factor to convert the given value from one unit to the other. For example, if we are given a mass of 10 grams, we can convert this to liters using the unit factor 1 gram = 1 liter. Thus, 10 grams = 10 liters.

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AThe half-life of an isotope is the amount of time it takes for half of the atoms in a sample to decay. If the half-life of a sample of uranium-234 is 2.5 * 10^5 years, it means that after 2.5 * 10^5 years, half of the atoms in the sample will have decayed.

If you want to know how long it will take for only one sixth of the original mass to be left, you can use the following formula:

t = (half-life) * log(2) / log(1/6)

Plugging in the values, we get:

t = (2.5 * 10^5 years) * log(2) / log(1/6)

This simplifies to:

t = 3.7 * 10^5 years

So it will take approximately 3.7 * 10^5 years for only one sixth of the original mass to be left.nswer:

An atom that has 13 protons and 14 neutrons will have mass number 27.

Rutherford demonstrated that an atom's nucleus, which is made up of protons and neutrons, contains the vast bulk of the atom's mass. The total number of protons and neutrons in an atom is referred to as the mass number. The number of protons(atomic number) and neutrons and their sum can be used to compute it.

We know that,

Mass number = Number of protons + Number of neutrons

= 13 + 14 = 27.

The mass number  is 27.

Therefore  an atom that have 13 protons and 14 neutrons will have mass number 27.

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The two portions on this module for which we can broaden unit elements to do dimensional analysis with chemical materials are volume and mass.

volume is a degree of the quantity of three-dimensional space occupied by using an object or substance. it's miles regularly measured in liters, cubic centimeters, or cubic meters. volume is used to measure the potential of a field, the dimensions of an object, or the quantity of liquid or gas in a given space. it's also used to determine the mass of an item, because the density (mass in line with unit quantity) is often acknowledged.

the 2 portions of volume and mass are critical for doing dimensional analysis with chemical substances because they help to measure the amount of a substance in distinct gadgets. extent is vital for measuring the quantity of liquid materials, and mass is critical for measuring the quantity of strong substances. each of these portions are vital for accurate and specific measurements of chemical substances, making them crucial for dimensional analysis.

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Answer:a pure substance consists only of one element or one compound. a mixture consists of two or more different substances, not chemically joined together

Explanation: