The recommended daily allowance of niacin (vitamin B3) is 12 mg per day for children. The molecular formula for niacin is C6H5NO2. Calculate the number of molecules of niacin in 12 mg .

Sulfur, selenium, and oxygen are nonmetals that have similar chemical properties due to which it is placed in a similar group.

The names of the non-metals which have similar or they have the same chemical properties are given below;

Sulfur, selenium, and oxygen are non-metals that have similar chemical properties. The sulfur, selenium, and oxygen belong to a group which is called the oxygen family.

The group 7 elements are known as halogens, they also contained very reactive non-metal elements.

The noble gases are in group 8A they have also the same chemical properties.

1. Sulfur, selenium, and oxygen have the same chemical properties. (true)

2. Non-metals are good conductors of electricity. (false)

3. Nonmetals react more with metals than with nonmetals. (true)

So we can conclude that sulfur, selenium, and oxygen are non-metals that have similar chemical properties due to which it is placed in a similar group.

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Which nonmetals have similar chemical properties? Check all that apply.

sulfur

nitrogen

selenium

oxygen

carbon

fluorine

Answer:

The correct answer would be 40 m/s

Explanation:

The reason 40 m/s is the correct answer is because m/s stands for meters per second.

Hope this helps you with what you're working on! :D

Answer:

40 m/s north

Explanation:

Velocity is a vector quantity, so it have both direction and magnitude.

Answer:

true

Explanation:

(a) The empirical formula of the compound is \(C_{29}H_ {36}O\)

(b) The molecular formula of the compound is approximately \(C_{8}H_{118}O_{3}\)

To determine the empirical formula of the organic compound, we need to find the simplest whole-number ratio of the elements present.

(a) The given percentages of carbon, hydrogen, and oxygen can be converted into moles by dividing them by their respective atomic masses:

Carbon: 0.624 g / 12.01 g/mol = 0.052 mol

Hydrogen: 0.065 g / 1.008 g/mol = 0.064 mol

Oxygen: 0.028 g / 16.00 g/mol = 0.0018 mol

Next, we divide each of the mole values by the smallest mole value (0.0018 mol in this case) to obtain the mole ratio:

Carbon: 0.052 mol / 0.0018 mol ≈ 29

Hydrogen: 0.064 mol / 0.0018 mol ≈ 36

Oxygen: 0.0018 mol / 0.0018 mol = 1

Therefore, the empirical formula of the compound is \(C_{29}H_ {36}O\)

(b) To find the molecular formula, we need the relative molecular mass of the compound, which is given as 1940 g/mol. The empirical formula mass can be calculated by summing the atomic masses in the empirical formula:

Empirical formula mass: (29 × 12.01 g/mol) + (36 × 1.008 g/mol) + (1 × 16.00 g/mol) = 588.94 g/mol

To find the multiplier, we divide the relative molecular mass by the empirical formula mass:

Multiplier: 1940 g/mol / 588.94 g/mol ≈ 3.29

Rounding to the nearest whole number, the molecular formula of the compound is approximately 3 times the empirical formula, resulting in \(C_{8}H_{118}O_{3}\).

In summary, the empirical formula of the compound is\(C_{29}H_ {36}O\), and the molecular formula is approximately \(C_{8}H_{118}O_{3}\).

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The amount of heat energy (in KJ) needed to convert 3 moles of water vapor into hydrogen gas and oxygen gas is 1450.8 KJ

We'll begin by writing the balanced equation. This is illustrated below:

2H₂ + O₂ --> 2H₂O ΔH = 483.6 KJ

From the balanced equation above,

2 moles of water (H₂O) required 483.6 KJ to produce hydrogen gas and oxygen gas

The heat energy needed to convert 3 moles of water can be obtained as illustrated below:

From the balanced equation above,

2 moles of water (H₂O) required 483.6 KJ to produce hydrogen gas and oxygen gas

Therefore,

3 moles of water (H₂O) will require = 3 × 483.6 = 1450.8 KJ to produce hydrogen gas and oxygen gas

Thus, we can conclude that the energy needed to convert 3 moles of water is 1450.8 KJ

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kilojoules of energy have to be removed to freeze 500 grams of water when it starts at 65 C 153.7kJ.

The strength we get from food and drinks is measured in kilojoules (kJ). this is the metric term for calories. Kilojoules and energy represent the equal issue. One calorie is about four kilos of calorie content material is frequently given in kcals, which is short for kilocalories, and additionally in kJ, which is brief for kilojoules.

A kilocalorie is another word for what is normally called a calorie, so 1,000 calories can be written as 1,000kcals. Kilojoules are the metric measurement of energy.

1200 kilojoules (kJ) are equal to 286. eight energy (kcal). The formula for converting kilojoules to calories is E (Cal) = E (kJ) x 0.239, and the reverse calculation is E (kJ) = E (Cal) / four.184. In other words, multiply the kJ price by means of zero.239 to get calories, and divide the kcal fee by way of four.184 to get kilojoules.

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Answer:

1.25 g.

Explanation:

5% or 25 g

= 0.05 * 25

= 1.25 g (answer).

D.) HF of the following molecules contain POLAR COVALENT bonds

A polar covalent link holds a hydrogen atom and a fluorine atom together in a hydrogen fluoride (HF) molecule.

The molecule that has a polar covalent link in it is c. H-F since fluorine and hydrogen atoms have different electronegativities, which causes the bond to become polarised.

A polar molecule is one that has a little positive charge on one end and a slight negative charge on the other. A polar molecule is a diatomic compound, such as HF, that has a polar covalent link.

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Answer:

5H2 + 4NO = 2N2 +4H2O + H2

Explanation:

Reactants:

Five molecules that contains two hydrogen = 5H2

Four molecules that contains one nitrogen and one oxygen = 4NO

Products:

Two molecules that contains two nitrogen = 2N2

Four molecules that contains one oxygen and two hydrogen = H2O

One molecules that contains two hydrogen = 1H2 or H2

The balanced chemical equation for the reaction will be: 5 H₂ + 4 NO → 2 N₂ + 4 H₂O + H₂, and there is no limiting reactant in this reaction.

To write the balanced chemical equation for the reaction, let's first identify the reactants and products based on the information provided:

Reactants:

5 molecules contain 2 white spheres (Hydrogen): 5 H₂

4 molecules contain 1 red (Oxygen) and 1 blue (Nitrogen) sphere: 4 NO

Products:

2 molecules contain 2 blue spheres (Nitrogen): 2 N₂

4 molecules contain 1 red (Oxygen) and 2 white (Hydrogen) spheres: 4 H₂O

1 molecule contains 2 white spheres (Hydrogen): 1 H₂

Now, let's write the balanced chemical equation by ensuring that the number of atoms of each element is the same on both sides of the equation:

Reactants: 5 H₂ + 4 NO

Products: 2 N₂ + 4 H₂O + 1 H₂

The balanced chemical equation for the reaction is:

5 H₂ + 4 NO → 2 N₂ + 4 H₂O + H₂

Now, let's determine the limiting reactant:

From the balanced equation, we can see that the stoichiometric ratio between H₂ and NO is 5:4. This means that for every 5 molecules of H₂, we need 4 molecules of NO for the reaction to proceed completely.

Since we have 5 molecules of H₂ and 4 molecules of NO, both reactants are present in the exact stoichiometric ratio required for the reaction. Therefore, neither H₂ nor NO is in excess, and both will be fully consumed during the reaction. As a result, there is no limiting reactant in this reaction.

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--The given question is incomplete, the complete question is

"Oxygen is represented by a red sphere. Nitrogen is represented by a blue sphere. Hydrogen is represented by a white sphere. In the reactants there are five molecules that contain two white spheres and four molecules that contains one red and one blue sphere. In the products there are two molecules that contain two blue spheres, four molecules that contain one red and two white spheres, and one molecule that contains two white spheres. What is the chemical formula for the limiting reactant in the reaction shown? chemical formula: Write the balanced chemical equation for the reaction, using lowest whole-number coefficients."--

Even with the additional energy input from increasing both the temperature and concentration, Reaction A will not proceed.

To determine if Reaction A will proceed after both increases, we need to calculate the total energy change for Reaction A.

First, let's calculate the energy change for increasing the temperature by 20°C:

ΔE1 = 50 J

Next, let's calculate the energy change for increasing the concentration by 4 M:

ΔE2 = 100 J

The total energy change for Reaction A is:

ΔEA = ΔE1 + ΔE2 + 300 J = 450 J

Since the current energy level of Reaction A is only 160 J, which is less than the required energy change of 450 J, Reaction A will not proceed even if we increase the temperature and concentration.

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Answer:=1

Explanation:H = 1, O = 16, C = 12, N = 14 and 14--13 = 1 and your answer is 1

Answer:

James Chadwick conducted an experiment where he assailed the element Beryllium with alpha particles that came from the radioactive decay of Polunium. The experiment results showed highly penetrating radiation emitted from the Beryllium. In this, Chadwick proposed that radiation consisted of uncharged particles, which were later founded as neutrons.

Answer:

349.503 g

https://www.convertunits.com/from/moles+Copper/to/grams

here is a link, you can convert moles of copper to grams here

The answer is 5.50 moles of Cu (Copper) has 349.503 grams mass .

A mole is defined as 6.02214076 × 10²³ atoms, molecules, ions, or other chemical units.

and the molar mass of a substance is defined as the mass of 1 mole of that substance, expressed in grams per mole.

It is equal to the mass of 6.022 × 10 23 atoms, molecules, or formula units of that substance.

1 mole of Cu has 63.546 grams of Cu

So 5.50 moles will have 5.50 * 63.546 grams

=349.503 grams

Therefore 5.50 moles of Cu (Copper) has 349.503 grams mass .

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Answer:

The answer is "35 atoms".

Explanation:

The Formula for isopropyl alcohol is: \(C_3H_8O\)

In 1 molecule of \(C_3H_8O\) = 8 atoms of hydrogen  

In 4 molecule of = atoms of hydrogen

According to the given formula \(C_3H_7O\)

In 5 molecule of \(C_3H_7O\) \(= 5 \times 7 = 35\) atoms of hydrogen.

Answer: The answer is D. The central atoms consist of two carbons.

Explanation:

Answer:

The central atoms consist of two carbons

Explanation:

Took the test! hope this helps!

Yes, s = u+v/2+t, where s is the displacement, u is the beginning velocity, v is the end velocity, and t is the time required, is the equation of motion for a body travelling with uniform acceleration.

The basic law of motion, which states that a body's rate of change in displacement is directly proportional to its velocity, provides the basis for this equation. The equation of motion for a body travelling with constant acceleration, s = ut + 1/2at2, may be used to derive it.

The equation of motion for a body travelling with uniform acceleration is given by replacing the value of an as (v-u)/t and getting s = u+v/2+t. This formula is only accurate when the body's acceleration is constant and uniform.

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Answer: the holy grail

Explanation: aaahhhhhhhh!

Answer:

Explanation:

a )

m = m₀ \(e^{-\lambda t\)

m is mass after time t . original mass is m₀ , λ is disintegration constant

λ = .693 / half life

= .693 / 1590

= .0004358

m = m₀ \(e^{- 0.0004358 t}\)

b )

m = 50 x \(e^{-.0004358\times 500}\)

= 40.21 mg .

c )

40 = 50 \(e^{-.0004358t\)

.8 = \(e^{-.0004358t\)

\(e^{.0004358t\) = 1.25

.0004358 t = .22314

t = 512 years .

Answer:

69.7 mL ≅ 70 mL

Explanation:

The chemical reaction between hydrobromic acid (HBr) and lithium metal (Li) produces lithium bromide (LiBr) and hydrogen (H₂) according to the following equation:

2HBr(aq) + 2Li(s) → 2LiBr(aq) + H₂(g)

Thus, 2 moles of HBr reacts with 2 moles of Li. So, the stoichiometric ratio is 1:1 (1 mol HBr reacts with 1 mol Li).

We convert the mass of Li to moles by using the molar mass (MM) of LiBr:

MM(LiBr) = 6.9 g/mol + 79.9 g/mol = 86.8 g/mol

moles of Li(s) = mass/MM(LiBr) = 19.4 g/86.8 g/mol = 0.223 moles Li(s)

Now, we can divide the moles of Li into the molarity of the HBr solution to obtain the volume in liters wee need to add:

V = moles Li(s)/M = (0.223 mol)/(3.2 mol/L) = 0.0697 L

0.0697 L x 1000 mL/1 L = 69.7 mL ≅ 70 mL

Therefore, 70 mL of 3.2 M HBr are needed to entirely dissolve the metal.

Answer:

in my opinion I think the answer the be "A"

Answer:

synthesis reaction

Explanation:

please mark me as brainlest

Answer:

7.5 g

Explanation:

There is some info missing. I think this is the original question.

Ammonium phosphate ((NH₄)₃PO₄) is an important ingredient in many fertilizers. It can be made by reacting phosphoric acid (H₃PO₄) with ammonia (NH₃). What mass of ammonium phosphate is produced by the reaction of 4.9 g of phosphoric acid? Be sure your answer has the correct number of significant digits.

Step 1: Write the balanced equation

H₃PO₄ + 3 NH₃ ⇒ (NH₄)₃PO₄

Step 2: Calculate the moles corresponding to 4.9 g of phosphoric acid

The molar mass of phosphoric acid is 98.00 g/mol.

\(4.9 g \times \frac{1mol}{98.00g} = 0.050mol\)

Step 3: Calculate the moles of ammonium phosphate produced from 0.050 moles of phosphoric acid

The molar ratio of H₃PO₄ to (NH₄)₃PO₄ is 1:1. The moles of (NH₄)₃PO₄ produced are 1/1 × 0.050 mol = 0.050 mol.

Step 4: Calculate the mass corresponding to 0.050 moles of ammonium phosphate

The molar mass of ammonium phosphate is 149.09 g/mol.

\(0.050mol \times \frac{149.09 g}{mol} = 7.5 g\)

Answer: what do u need help with ?

Explanation:

Answer: D) It conducts electricity when it is dissolved in water

A piece of chalk, CaCO₃, has an initial mass of 43.5 grams. The mass of the chalk decreased to 39.6 grams after use. Moles of chalk that were used is 0.039 moles where atomic mass of CaCo₃ is 100g.

A mole must be specified or be based on something reproducible, like all other units. The number of atoms in a sample of the isotope carbon-12 was once the basis for the current definition of the mole, which is now based on other factors.

Today, a mole is exactly 6.022×10²³, which equals Avogadro's number of particles. For all intents and purposes, the mass of one mole of a substance in grams and the mass of one molecule in daltons are essentially equivalent.

Formula for mole,

\(\frac{Mass of given substance}{Atomic mass of substance}\)

substituting values,

Initial moles = 0.0435

Final moles=0.0396

moles of chalk used=0.039

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Compared to crushed pills, loose powder medications have a higher surface area, which allows for faster body absorption and disintegration, leading to a speedier effect.

The drug's surface area has a direct relationship with the dissolving rate. Higher dissolving rates may be attained by reducing the particle size since surface area grows as particle size decreases.

Therefore, disintegration agents are added to formulations to encourage the breakdown of tablets into minute granules and their component particles. This enables a faster liberation of the drug particles from the tablet matrix, increasing the surface area for subsequent dissolving.

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Answer:

Plants need chloroplasts to capture light energy.

Plant cells use light energy to make food.

The cell uses the energy from food.

Hope it helps ;)

The quotient of the given mathematical problem is equal to 2. Therefore, option A is correct.

In arithmetic, a quotient can be described as a quantity produced by the division of two numbers. The quotient has used throughout mathematics and is referred to as the integer part of a division or as a fraction or a ratio.

A rational number is the quotient of two integers when the denominator is non-zero.

A real number r is rational, it can be expressed as a quotient of two integers with a non-zero denominator.

Given a real number r, r is rational if and only if there exist integers a and b such that\({\displaystyle r={\tfrac {a}{b}}}, {\displaystyle b\neq 0}\)

Given, the division of √100/√25

We can write the \(\sqrt{100} =\sqrt{25\times 4} =\sqrt{25} \sqrt{4}\)

Now, \(\displaystyle \frac{\sqrt{100}}{\sqrt{25}}= \frac {\sqrt{25}\times \sqrt{4} }{ \sqrt{25}} =\sqrt{4} =2\)

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The measure of the length of events and the duration of intervals between events is time.

The duration of events or the gaps between them can be measured, compared, or even ordered using time. The lengthy period of time that the Earth's geologic history takes up is known as geologic time. Starting at the beginning of the Archean Eon  formal geologic time runs until the present. Geology is defined as the "Science of the Earth."

Geology is the fundamental Earth science that examines how the earth created, its structure and composition, and the various forces acting on it. It is sometimes known as geoscience or earth science.

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The question is incomplete, the complete question is shown in the image attached to this answer.

Answer:

a) Br^-

b) FeCl3

c) slower

d) see the first attached image

Explanation:

Aromatic compounds undergo electrophilic substitution sections in the presence of the appropriate electrophile.

In the reaction above, the Br^- nucleophile attacks the Lewis acid FeCl3. Recall that the nitro group is meta directing hence the incoming Br^+ electrophile is directed towards the meta position as shown in the image attached.

Note that the nitro group deactivates the ring towards electrophilic substitution hence the reaction is slower with nitrobenzene than with unsubstituted benzene.