cho một thực phẩm có độ ẩm tương đối là 81 hỏi hoạt độ nước trong thực phẩm đó là bao nhiêu

Answers

Answer 1

Explanation:

For a food with a relative humidity of 81, what is the water activity in the food?

Water activity in a food = relative humidity / 100

Substitute the given values in this formula to get water activity:

Water activity in a food = 81 / 100

Hence, water activity =0.81


Related Questions

A sample of oxygen gas at a pressure of 1.19 atm and a temperature of 24.4 °C, occupies a volume of 18.7 liters. If the gas is allowed to expand at constant temperature to a volume of 29.4 liters, the pressure of the gas sample will be ______ atm.

Answers

Answer:

[tex]\boxed {\boxed {\sf 0.757 \ atm}}[/tex]

Explanation:

We are asked to find the pressure of a gas given a change in volume. Since the temperature remains constant, we are only concerned with volume and pressure. We will use Boyle's Law, which states the volume is inversely proportional to the pressure. The formula for this law is:

[tex]P_1V_1= P_2V_2[/tex]

Initially, the oxygen gas occupies a volume of 18.7 liters at a pressure of 1.19 atmospheres.

[tex]1.19 \ atm * 18.7 \ L = P_2V_2[/tex]

The gas expands to a volume of 29.4 liters, but the pressure is unknown.

[tex]1.19 \ atm * 18.7 \ L = P_2 * 29.4 \ L[/tex]

We are solving for the new pressure, so we must isolate the variable [tex]P_2[/tex]. It is being multiplied by 29.4 liters. The inverse operation of multiplication is division. Divide both sides of the equation by 29.4 L.

[tex]\frac {1.19 \ atm * 18.7 \ L}{29.4 \ L} =\frac{ P_2 * 29.4 \ L}{29.4 \ L}[/tex]

[tex]\frac {1.19 \ atm * 18.7 \ L}{29.4 \ L} =P_2[/tex]

The units of liters cancel.

[tex]\frac {1.19 \ atm * 18.7 }{29.4 } =P_2[/tex]

[tex]\frac {22.253}{29.4 } \ atm = P_2[/tex]

[tex]0.7569047619 \ atm =P_2[/tex]

The original measurements all have 3 significant figures, so our answer must have the same. For the number we calculated, that is the thousandth place. The 9 in the ten-thousandth place to the right of this place tells us to round the 6 up to a 7.

[tex]0.757 \ atm \approx P_2[/tex]

The pressure of the gas sample is approximately 0.757 atmospheres.

Answer:

According to Boyle's law, for a given mass of ideal gas, pressure of gas is inversely proportional to the volume of gas, Provided the Temprature remains constant.

P₁ = 1.19 atmP₂ = ?V₁ = 18.7 LV₂ = 29.4 LT = constant = 24.4° C = Isothermal process

[tex]\implies \sf P_1 V_1 = P_2 V_2 \\ [/tex]

[tex]\implies \sf 1.19 \times 18. 7= P_2 \times 29.4 \\[/tex]

[tex]\implies \sf 22.253= P_2 \times 29.4 \\[/tex]

[tex]\implies \sf P_2 = \dfrac{22.253}{29.4} \\[/tex]

[tex]\implies \underline{ \red{\boxed{ \bf P_2 \approx0.756 \: atm }}} \\[/tex]

A piece of metal has a volume of 30.0cm3 and a mass of 252g. What is its density? what metal do you think this is?

Answers

Answer:

Explanation:

get density = D = m / V = 0.252 / 0.00003 = 8400 metal will be Cu => bronze

oxidation number of Ni in Ni(CO)4 is​

Answers

Answer:

0

Explanation:

answer from gauth math

For the following reaction, 5.29 grams of water are mixed with excess diphosphorus pentoxide. The reaction yields 13.3 grams of phosphoric acid . diphosphorus pentoxide(s) + water(l) phosphoric acid(aq). What is the theoretical yield of phosphoric acid?

Answers

Answer:

19.2 g

Explanation:

Step 1: Write the balanced equation

P₂O₅(s) + 3 H₂O(l) ⇒ 2 H₃PO₄

Step 2: Calculate the moles corresponding to 5.29 g of H₂O

The molar mass of H₂O is 18.02 g/mol.

5.29 g × 1 mol/18.02 g = 0.294 mol

Step 3: Calculate the theoretical yield of phosphoric acid, in moles

The molar ratio of H₂O to H₃PO₄ is 3:2. The theoretical yield of H₃PO₄ is 2/3 × 0.294 mol = 0.196 mol

Step 4: Calculate the mass corresponding to 0.196 moles of H₃PO₄

The molar mass of H₃PO₄ is 97.99 g/mol.

0.196 mol × 97.99 g/mol = 19.2 g

A student isolated an unknown organic compound through extraction. The student measures the melting point and fins it to be 115-122 C. The student looks through the list of possible strucures and decides the comound is most likely 2-napthol. Do you believe this choice is correct?

Answers

Hope this helps!

https://www.chegg.com/homework-help/questions-and-answers/student-isolated-unknown-organic-compound-extraction-student-measures-melting-point-finds--q77093697

Calculate the solubility of copper(II) hydroxide, Cu(OH)2, in g/L​

Answers

Answer:

Ksp = [ Cu+² ] [ OH-] ²

molar mass Cu(oH )2 ==> M= 63.546 (1) + 16 (2) + 1 (2) = 97.546 g/mol

Ksp = [ Cu+² ] [ OH-] ²

Ksp [ cu (OH)2 ] = 2.2 × 10-²⁰

|__________|___Cu+² __|_2OH-____|

|Initial concentration(M)|___0__|_0______|

|Change in concentration(M)|_+S |__+2S__|

|Equilibrium concentration(M)|_S _|2S___|

Ksp = [ Cu+² ] [ OH-] ²

2.2 ×10-²⁰ = (S)(2S)²= 4S³

[tex]s = \sqrt[3]{ \frac{2.2 \times {10}^{ - 20} }{4} } = 1.8 \times {10}^{ - 7} [/tex]

S = 1.8 × 10-⁷ M

The molar solubility of Cu(OH)2 is 1.8 × 10-⁷ M

Solubility of Cu (OH)2 =

[tex]Cu (OH)2 = \frac{1.8 \times {10}^{ - 7} mol \:Cu (OH)2 }{1L} \times \frac{97.546 \: g \: Cu (OH)2}{1 \: mol \: Cu (OH)2} \\ = 1.75428 \times 10 ^{ - 5} [/tex]

Solubility of Cu (OH)2 = 1.75428 × 10 - g/ L

I hope I helped you^_^

Balance the following equations Ag (s) + H₂ S(g) + 0₂ (g) → Ag₂ S(₅) + H₂0

Answers

Answer:

2Ag(s) + 2H²S(g) + O2(g) ➡️ Ag2S(s) + 2H2O(g)

Explanation:

Sorry for my typo. but you understand

An outdoor gear company develops a new type of fabric that works with electricity to warm the body without interfering with motion like heavy jackets do. Research biologists, studying life in extremely cold conditions on the polar ice caps, begin wearing the new fabric because it helps them work more comfortably, and they find it increases their productivity.

What best describes how the processes of scientific investigation and technological design are involved in this situation?

The clothing company conducted a scientific investigation to communicate results to researchers, who then used the knowledge in a technological design.
The clothing company conducted a scientific investigation to produce a product that researchers could then test while designing new technology.
The clothing company used technological design to create a product that helped aid researchers conducting a scientific investigation.
The clothing company designed a new technology that provided information researchers needed in order to continue with their scientific investigation.

Answers

The answer is C. The clothing company used technological design to create a product that helped aid researchers conducting a scientific investigation.

Answer:

C: The clothing company used technological design to create a product that helped aid researchers conducting a scientific investigation.

Explanation:

I just did the assignment on EDGE2020 and it's 200% correct!  

Also, heart and rate if you found this answer helpful!! :) (P.S It makes me feel good to know I helped someone today!!)  :)  

Please help with all 3 parts!

Answers

Answer:

1:Part A.

[tex]\bold{42.2 g C_{12}H_{22}O_{11} \:in \:528 g H₂O}[/tex]

Mass Percent=[tex]\bold{\frac{Mass\: of \:Solute}{Mass\: of \:Solution}×100\%}[/tex]

=[tex]\frac{42.2}{528}*100\%=\bold{\underline{7.99\: or \:8\%}}[/tex]

Part B.

[tex]\bold{198\:m g\: C_{6}H_{12}O_{6} \:in\:4.71 g\: H₂O}[/tex]

mass of solute: 198mg

mass of solvent :4.71g=4710g

Mass Percent=[tex]\bold{\frac{Mass\: of \:Solute}{Mass\: of \:Solution}×100\%}[/tex]

=[tex]\frac{198}{4710}*100\%=\bold{\underline{4.20\%}} [/tex]

Part C.

[tex]\bold{8.85 g NaCl \:in \:190 g\: H₂O}[/tex]

Mass Percent=[tex]\bold{\frac{Mass\: of \:Solute}{Mass\: of \:Solution}×100\%}[/tex]

=[tex]\frac{8.85}{190}*100\%=\bold{\underline{4.66\%}}[/tex]

Answer:

It will help you !!!!!!!!!!

What is the formula for the compound made from mercury (II) and the nitrate ion.

Answers

Answer:

Hg(NO3)2

Explanation:

Hg occurs both as Hg(I) and Hg(II) but nitrate is -1, not -2 We NORMALLY use the smallest set of subscripts but in the case of Hg(I) compounds, most of them are dimeric. Hg2Cl2, Hg2(NO3)2, etc. Note that there also is a mercury(II) nitrate; i.e., Hg(NO3)2. Therefore, although the empirical formula for mercury(I) nitrate is HgNO3, the molecular formula is Hg2(NO3)2 anf I was always encouraged to write the molecular formula instead of the empirical formula.

Hope this helps! Feel free to shoot me any questions <3

How does a smoke detector utilize radiation?

A. Beta radiation creates a stead stream of electrons. When the stream is broken by smoke particles, it sets off the alarm.
B. Alpha radiation ionizes the air. When smoke interacts with the ionized particles it causes the alarm to sound.
C. Gamma radiation creates a stead stream of electrons. When the stream is broken by smoke particles, it sets off the alarm.
D. Beta radiation ionizes the air. When smoke interacts with the ionized particles it causes the alarm to sound.

Answers

D. Beta radiation ionizes the air. When smoke
interacts with the ionized particles it causes the
alarm to sound.

HELP! How is the mass number of an atom calculated?
A - total number of electrons

B - total number of protons

C - protons plus neutrons

D - electrons plus neutrons

Answers

The answer is C. Mass number = protons + neutrons

The first step of electrophilic aromatic substitution involves the formation of the arenium ion intermediate.

a. True
b. Fasle

Answers

Answer:

True

Explanation:

Aromatic compounds undergo substitution rather than addition reactions because the aromatic structure is maintained.

Electrophilic aromatic substitution begins with attack of the electrophile on the aromatic ring to yield a delocalized intermediate called the arenium intermediate. Loss of hydrogen from this intermediate yields the final product.

c6h5-c=o-ch3 + br2/oh

Answers

Explanation:

here's the molecule you were looking for

how do elasticity ang flexibility differ?

Answers

Answer:

the object will regain its original form as soon as the deforming force is removed. ... Flexibility means the object is just easily deformed, and will stay that way.

Explanation:

Identify the compound with ionic bonds.
CO
H2O
Ne
KCl
O2

Answers

Answer:

CO =Coordinate Covalent Bond ,H2O = Water , NE= Nickel or Neon ,KCL=Potassium Chloride and O2 = Water

Explanation:

hope you wiill get help from me please follow me

What is the source of energy stored by ATP in cells?
Answers

A.
oxidation of biological compounds

B.
reduction of biological compounds

C.
synthesis of biological compounds

D.
polymerization of biological compounds

Answers

Answer:

I think C (synthesis of biological compounds

Explanation:

have a nice day

Hydrogen is manufactured on an industrial scale by this sequence of reactions:

CH4(g) + H2O(g) ⇆ CO(g) + 3H2(g)
CO(g)+ H2O(g) ⇆ CO(g) + H2(g)

The net reaction is:
CH4(g) + H2O(g) ⇆ CO(g) + 4H2(g)

Write an equation that gives the overall equilibrium constant K in terms of the equilibrium constants K1 and K2.

Answers

Answer:

[tex]K=K_1*K_2\\\\K=\frac{[H_2]^3[CO_2][H_2]}{[CH_4][H_2O][H_2O]}[/tex]

Explanation:

Hello there!

In this case, for the given chemical reaction, it turns out firstly necessary to write the equilibrium expression for both reactions 1 and 2:

[tex]K_1=\frac{[CO][H_2]^3}{[CH_4][H_2O]} \\\\K_2=\frac{[CO_2][H_2]}{[CO][H_2O]}[/tex]

Now, when we combine them to get the overall expression, we infer these two are multiplied to get:

[tex]K=K_1*K_2\\\\K=\frac{[CO][H_2]^3}{[CH_4][H_2O]} *\frac{[CO_2][H_2]}{[CO][H_2O]}\\\\K=\frac{[H_2]^3[CO_2][H_2]}{[CH_4][H_2O][H_2O]}[/tex]

Regards!

The density of a gas cannot be measured.
True
False

Answers

Answer:

False

Explanation:

Answer:

False

Explanation:

uses of rare or inert gases

Answers

Explanation:

noble gases are useful let's take for instance helium which is used in balloons. they are used to form inert atmosphere and they are used also to deter chemical reaction.

Carboxylic acid derivatives undergo hydrolysis to make carboxylic acids.

a. True
b. False

Answers

Answer:

TRUE

Explanation:

All carboxylic acid derivatives have in common the fact that they undergo hydrolysis (a cleav- age reaction with water) to yield carboxylic acids. with hydroxide ion to yield a carboxylate salt and an alcohol. The carboxylic acid itself is formed when a strong acid is subsequently added to the reaction mixture.

PLS MARK BRAINLIEST

True

All carboxylic acid derivatives have in common the fact that they undergo hydrolysis (a cleav- age reaction with water) to yield carboxylic acids. with hydroxide ion to yield a carboxylate salt and an alcohol. The carboxylic acid itself is formed when a strong acid is subsequently added to the reaction mixture.
PLS MARK BRAINLY PLSSSSSSS

The Bohr effect:_____.
a. explains through the Bohr model of the atom why Fe2+ will bind O2 in heme but Fe3+ will not.
b. contributes to binding of O2 by hemoglobin in lungs and release of O2 from hemoglobin in tissues.
c. applies to both myoglobin and hemoglobin.
d. relates [H+] to [CO2].

Answers

Answer:

b. contributes to binding of O2 by hemoglobin in lungs and release of O2 from hemoglobin in tissues.

Explanation:

The Bohr effect is a phenomenon described by Christian Bohr. Is an affinity that binds oxygen and hemoglobin and is inversely related to the concentration of carbon dioxide. As CO2 reacts with water and an increase in CO2 results in a decrease in blood ph.

Compounds such as butane and isobutane that have the same molecular formula but differ in the order in which the atoms are connected are called ____________

a. trans isomers

b. cis isomers

c. conventional isomers

d. constitutional isomers​

Answers

Answer:

One compound, called n-butane, where the prefix n- represents normal, has its four carbon atoms bonded in a continuous chain. The other, called isobutane, has a branched chain. Different compounds that have the same molecular formula are called isomers.

Answer:

d. constitutional isomers​

Explanation:

i hope it will help

Do the tests performed to identify DNA exclude the presence of RNA?

Answers

DNA and RNA can also be ISOLATED from the same biological sample.

So the answer is no, both DNA and RNA are together.

Answer:

so the answer is no

both DNA and RNA are together.

Explanation:

DNA and RNA can also be ISOLATED from the same. biological sample

Hypercalcemia sign and symptoms severe symptoms

Answers

Answer:

Hypercalcemia can cause stomach upset, nausea, vomiting and constipation. Bones and muscles. In most cases, the excess calcium in your blood was leached from your bones, which weakens them. This can cause bone pain and muscle weakness.

Some symptoms are:

Fatigue, bone pain, headaches.

Nausea, vomiting, constipation, decrease in appetite.

Forgetfulness.

Lethargy, depression, memory loss or irritability.

Muscle aches, weakness, cramping and/or twitches.

How to prepared sodium chloride solution.​

Answers

Explanation:

Dissolve 93.52g of NaCl in about 400mL of distilled water, then add more water until final volume is 800mL. If starting with a solution or liquid reagent: When diluting more concentrated solutions, decide what volume(V2) and molarity (M2) the final soluble should be.

tính ΔH° của phả ứng sau ở 200°C
CO+1÷2O=CO2
ΔH°

Answers

Could u explain more.?

explain in details how triacylglycerol have an advantage over carbohydrates as stored fuel

Answers

Answer:

As stored fuels, triacylglycerols have two significant advantages over polysaccharides such as glycogen and starch. The carbon atoms of fatty acids are more reduced than those of sugars, and oxidation of triacylglycerols yields more than twice as much energy, gram for gram, as that of carbohydrates.

Explanation:

How many milliliters of 0.204 Mol KMnO4 are needed to react with 3.24 g of iron(II) sulfate, FeSO4? The reation is as folows. 10FeSO4(aq) + 2 KMnO4(aq) = 5Fe2(SO4)3(aq) + 2MnSO4(aq) + K2SO4(aq) + 8H2O(l)​

Answers

Answer:

Explanation:

nFeSo4=3.36/152

nkmno4=1/5nFeSO4

V=17.68 ml

cuales son las caracteristicas de el livermorio

Answers

Answer:

Livermorium is a radioactive, artificially produced element about which little is known. It is expected to be a solid and classified as a metal. It is a member of the chalcogen group. Livermorium has four isotopes with known half-lives, all of which decay through alpha decay

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