Which is an unreliable source?

A scientist who studies dinosaurs presents her research on velociraptors at a science convention.
An advertisement for acne medication claims it can clear up acne in less than one week.
An article on the Centers for Disease Control and Prevention (CDC) website discusses the salmonella bacteria.
A chemistry teacher discusses possible projects for the upcoming science fair.

Answer:

4 moles

Explanation:

For every mole of deuteriomethane consumed, 4 moles of water are produced.

So, the answer is 4 moles

Answer:

a)CaCO 3→CaO+CO 2CaCO3→CaO+CO2

b) Moles of CaCO3=4.37moles

c) I) Mass of calcium oxide =28g

ii)Mass of carbon dioxide=16.7g

iii)Volume=203cm3

Answer:

C. It is the ratio of the concentrations of products to the

concentrations of reactants.

Explanation:

Answer:

chemical formula of isopropyl alcohol can also be written as: C3H7OH, CH3CHOHCH3 or (CH3)2CHOH.

chemical formula of ethanoic acid is CH₃COOH.

Answer:

3600J

Explanation:

Q = mc∆T

= 50 x 0.9 x (100 - 20)

= 3600J

Answer:

About energy transfers:

Explanation:

When there is an energy transfer energy is neither created, nor destroyed. This means when that when one energy store decreases, one or more others must increase.

From the calculations, we can see that the theoretical yiled of NO2 is 100L of NO2

The theoretical yield is that calculated from the stoichiometry of the reaction.

We can see that 1 mole of O2 produced 2 moles of NO2. Thus;

2.23 moles of O2 will produce 4.46 moles of NO2

Since 1 mole of NO2 occupies 22.4 L

4.46 moles of NO2 occupies 100L of NO2

Learn more about theoretical yield:https://brainly.com/question/14966377

#SPJ1

Answer:

Electrons of an atom can affect chemical reactions, because electrons have a negative charge, which can introduce a form of energy.

After Rounding off The percentage yield is 64%

It is the ratio of actual yield to theoretical yield multiplied by 100% .

It is given in the question

20.0 g of bromic acid, HBrO3, is reacted with excess HBr.

The reaction is

HBrO₃ (aq) + 5 HBr (aq) → 3 H₂O (l) + 3 Br₂ (aq)

Actual yield = 47.3 grams

Molecular weight of Bromic Acid is 128.91 gram

Moles of Bromic Acid = 20/128.91 = 0.155 mole

Mole fraction ratio of Bromic Acid to Bromine is 1 :3

Therefore for 0.155 mole of Bromic Acid 3 * 0.155 = 0.465 mole of Bromine is produced.

1 mole of Bromine = 159.8 grams of Bromine

0.465 of Bromine = 74.31 grams of Bromine

Percentage Yield = (47.3/74.31)*100 = 63.65 %

After Rounding off The percentage yield is 64% .

To know more about Percentage Yield

brainly.com/question/22257659

#SPJ1

Answer:

74g

Explanation:

The other person had said that the Percentage Yield = (47.3/74.31)*100 = 63.65 %

So, since to find the percent yield you have to divide the actual yield by the theoretical yield, I would assume the theoretical yield is 74.31g (74g if you round to the nearest gram)

Answer:

hello :)

Explanation:

Water vapor in the air reaches its dew point as it cools in the air around the can, forming liquid drops of water. Condensation is the process where water vapor becomes liquid.

Answer:

1940K and 1939K Isotopes are two forms of the same element that have different numbers of neutrons in the nucleus. This means same symbol, and same atomic number (subscript), but different mass number (superscript).

Answer:

Here's your answer.

M(C3H8) = 44 g/mol

n(C3H8) = 5000 (g)/44 (g/mol) = 113,6 mol

[tex] N = n \times N_{a} = 113,6 \times 6,02 \times {10}^{23} \\ \\ = 684,1 \times 10 ^{23} \sf{molecules} [/tex]

The quantity of morphine, the nurse should administer is 0.3 ml.

Morphine is a drug which comes under the pain relieving drugs.

The quantity of morphine is 0.05 mg/kg

The weight of the baby is 3 kg.

Available morphine is 0.5 mg/mL.

0.05 x 3 = 0.15 mg

then, 0.15 mg / 0.5 = 0.3

Thus, the quantity of morphine, the nurse should administer is 0.3 ml.

Learn more about morphine

https://brainly.com/question/10665765

#SPJ1

A negative enthalpy (ΔH)for a molecule means energy was released when the molecule went through a phase change.

The enthalpy change of a reaction is the amount of heat absorbed or released as the reaction takes place.

Also, the amount of energy required to change the phase of a material is known as the enthalpy,

A negative enthalpy entails the amount of energy released during an exothermic reaction.

Thus, a negative enthalpy (ΔH)for a molecule means energy was released when the molecule went through a phase change.

Learn more about enthalpy here: https://brainly.com/question/14047927

#SPJ1

Explanation:

select the correct answer from each drp down

Volume=1600cm³=1.6dm³=1.6L

Temperature=25°C=273+25=298K

Pressure=75000Pa

Now

Apply ideal gas equation

The number of moles needed is

n=48.43mol.

Calculations

Given the values of the volume and temperature, we would convert them to the required units.

Volume=1600cm³=1.6dm³=1.6L

Temperature=25°C=273+25=298K

Pressure=75000Pa

We would use the ideal gas equation

PV=nRT

n=PV/RT

n=75000(1.6)/8.314(298)

n=48.43mol

Explanation:

1 moles Lead(II) Acetate to grams = 325.28804 grams

3.47 moles Lead(II) Acetate to grams = 325.28804 ×3.47 grams=1128.749 grams

1 moles sodium chloride to grams=58.5 grams

3.47 moles sodium chloride to grams=58.5×3.47 grams

=202.995 grams

Answer: B. [tex]\text{CH}_{3}\text{COO}^{+}[/tex]

Explanation:

To find the conjugate base, you add a hydrogen ion and add 1 to the overall charge.

CH[tex]_3[/tex]COO⁻ is the conjugate base of  CH[tex]_3[/tex]COOH in the given reaction. Therefore, the correct option is option B.

Conjugate acids and bases are ideas included in the Bronsted-Lowry acid-base theory. An acid losses a hydrogen ion as it splits into its electrons in water. The conjugate base of the acid is the species that results.

A conjugate base comprises the base participant, X-, of two compounds that convert into one another by acquiring or losing a proton, according to a more comprehensive definition. In a chemical process, the conjugate base has the capacity to either gain and absorb a proton. The proton and hydrogen is given away in the process by the conjugate acid. CH[tex]_3[/tex]COO⁻ is the conjugate base of  CH[tex]_3[/tex]COOH in the given reaction.

Therefore, the correct option is option B.

To know more about conjugate base, here:

https://brainly.com/question/30225100

#SPJ7

In order to prepare a 50-fold diluted enzyme, 0.1 mL of the stock solution of the enzyme is taken and made up to 5.0 mL with 0.001M HCl.

Dilution is a process whereby a solution of lower concentration is prepared from one of a higher concentration.

Dilution is done by using the dilution formula below:

C1; Initial concentration of enzyme = 1 mg/mL

C2; Final concentration of enzyme = 1/50 mg/ml = 0.02 mg/ml

V1; Initial volume of enzyme = y

V2; Final volume = 5.0 ml

V1 = C2V2/C1

V1 =  0.02 * 5/1 = 0.1 mL

Therefore, in order to prepare a 50-fold diluted enzyme, 0.1 mL of the stock solution of the enzyme is taken and made up to 5.0 mL with 0.001M HCl.

Learn more about dilution at: https://brainly.com/question/24881505

#SPJ1

Answer: 9.27 g/mL

Explanation:

[tex]d=\frac{m}{v}=\frac{18.53}{2.0}=\boxed{9.27 \text{ g/mL}}[/tex]

Answer:

A.DNA

Explanation:

Ahaa Its gona be right

Answer:

D.N.A.

Explanation:

Hi student! Let me help you out on this question.

D.N.A. is the molecule which carries instructions for inherited traits.

[tex]\therefore,Option\quad A \quad is \quad correct[/tex]

Hope that this helped! have a good day ahead.

5.1434 contains 5 significant figures and 4 decimals.

All zeros that occur between any two non-zero digits are significant. For example, 108.0097 contains seven significant digits.

Calculation:

5.1234 + 0.033÷ 1.650 = 5.1434

5.1434 contains 5 significant figures and 4 decimals. 5.1434 rounded to 4 sig figs is 5.143, to 3 sig figs is 5.14, and to 2 sig figs is 5.1.

Learn more about the significant figure here:

https://brainly.com/question/14359464?

#SPJ1

42.4 ml is the volume in milliliters of the lead ball if a lead ball is added to a graduated cylinder containing 50.6 ml of water.

A tall narrow container with a volume scale is used especially for measuring liquids.

The graduated cylinder contains water

mL is a volume unit.

Water volume = 50.6 ml

The lead ball caused an increase in volume from 50.6 ml to 93.0 mL.

The new volume is the lead ball volume plus the original water volume :

Final volume = Vlead ball+ Water original volume

[tex]93.0 mL= V_(lead ball) +50.6 ml[/tex]

[tex]V_(lead ball) = 93.0 mL - 50.6 ml[/tex]

[tex]V_(lead ball) = 42.4 ml[/tex]

Hence, 42.4 ml is the volume in milliliters of the lead ball.

Learn more about the graduated cylinder  here:

https://brainly.com/question/13386106

#SPJ1

Answer:

Explanation:

4NH₃ (g) + 3O₂ (g) ⇒ 2N₂ (g) + 6H₂ O(1)

Δ[tex]H_r={\sum}{ \Delta }H_f(\text{product})-{\sum}{ \Delta }H_f(\text{reactant})[/tex]

ΔH r =(2ΔH f(N 2 )+6ΔH f (H 2 O(l)))−(4ΔH f​ (NH 3 (g))+3ΔH f (O 2 (g)))

ΔH rex =[2×0+6×(−286)]−[4×(−46)+3×0]=−1716+186

ΔH rex =−1532kJ/mol

Thermodynamics is a branch of physical chemistry that studies heat and its effects and interactions. Governed by the four main laws, thermodynamics plays a huge role in physics and chemistry, and is also responsible for the law of conservation of energy, a fundamental rule in science.

The 4 ways to increase the concentration of chlorine molecules is listed below and the reaction will go into reverse if cooled.

Le Châtelier's principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium shifts to counteract the change to reestablish an equilibrium.

Energy + HCl (g) + ClNO₃ ⇄  Cl₂  + HNO₃

a. So in this reaction when at equilibrium , To increase the concentration of Chlorine molecules

1. An increase in Temperature will favour the formation of Chlorine molecules.

2. Decrease in concentration of Chlorine , or partial removal of Chlorine will result the equation to go in forward direction.

3.An Increase in the concentration of HCl will favour formation of Chlorine molecules.

4.An Increase in the concentration of  CINO₃ will also favour formation of Chlorine molecules.

b. The cooling would shift the reaction into backward direction as it is an endothermic reaction in forward state.

To know about reaction Le Châtelier’s principle

https://brainly.com/question/12099569

#SPJ1

[tex]\\ \rm\Rrightarrow Density=\dfrac{Mass}{Volume}[/tex]

[tex]\\ \rm\Rrightarrow Volume=\dfrac{Mass}{Density}[/tex]

[tex]\\ \rm\Rrightarrow Volume=\dfrac{0.19}{0.0076}[/tex]

[tex]\\ \rm\Rrightarrow Volume=25cm³[/tex]

[tex]\\ \rm\Rrightarrow Volume=25mL[/tex]

No of molecules=26.02×10²³molecules

No of moles

Molar mass

Mass

[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{Molecules}{Avagadro\:no}[/tex]

[tex]\\ \tt{:}\longrightarrow No\:of\:moles=\dfrac{26.02\times 10^{23}}{6.023\times 10^{23}}[/tex]

[tex]\\ \tt{:}\longrightarrow No\:of\:moles=4.32mol[/tex]

We need the mass

[tex]\\ \tt{:}\longrightarrow No\:of\:moles\times molar\:mass[/tex]

[tex]\\ \tt{:}\longrightarrow 32(4.32)[/tex]

[tex]\\ \tt{:}\longrightarrow 138.24g[/tex]

The given equilibrium reaction indicates the reaction between carbon monoxide and the oxygen and forms carbon dioxide. In this reaction, by increasing the concentration of the carbon monoxide, the equilibrium shifts towards the right. Since, the reactant concentration increases, the equilibrium stress decreases the concentration of the reactants and therefore, the equilibrium shift towards the right side of the equation.

reaction indicates that carbon monoxide reacts with oxygen and forms carbon dioxide gas.

By increasing the concentration of carbon monoxide image, the equilibrium in the reaction shifts towards the right.

The effect of change of pressure, concentration and temperature on the state of equilibrium can be predicted with the help of a principle known as Le Chatelier's principle. Here by increasing the concentration of CO₂, the amount of CO formation can increase.

If a system in equilibrium is subjected to a change in concentration, pressure or temperature, the equilibrium shifts in the direction that tends to reduce or to counteract the effect of change. When the concentration of any substance in equilibrium is increased, the equilibrium shifts in the direction which decreases the concentration of that substance.

On other hand, increasing the concentration of any of the products results in shifting the equilibrium in the backward reaction forming more products. So here increasing the amount of CO₂, shifts equilibrium in the backward direction and forms more amount of CO.

To know more about Le Chatelier's principle, visit;

https://brainly.com/question/31664161

#SPJ2

2.99 °C is the change in temperature if a 40 g sample of water absorbs 500 calories of energy.

The specific heat capacity is defined as the quantity of heat (J) absorbed per unit mass (kg) of the material when its temperature increases 1 K (or 1 °C), and its units are J/(kg K) or J/(kg °C).

Given data:

m = 40 g

Q = 500 J

Specific heat capacity of water = 4.18 J/g°C

Change in Temperature =?

The formula for Heat Energy is given by:

Q = mcp∆T

where: Q - Heat Energy

m - mass

cp - specific heat

∆T = change in temperature, [tex]T_2 - T_1[/tex]

Solution:

Substituting the value of m, specific heat capacity of water and Q in the formula,

500 J = (40 g)(4.18 J/g°C)(∆T)

∆T = 2.99 °C

Learn more about the specific heat capacity here:

https://brainly.ph/question/7099790

#SPJ1