A coffee cup calorimeter will not be used to
directly measure the enthalpy of magnesium
combustion because

✓ the coffee cups could melt.

The calorimeter is made of coffee cups instead of
a beaker because coffee cups are

✓ better insulators

than beakers.

You will not measure the enthalpy of the reaction
of

✓ H2 and 02

in the coffee cup calorimeter because this reaction involves gases
Instead, you will use a well-known published
value.

These are the correct answers on edge 2021

Answer:

Evaporation happens when a liquid substance becomes a gas. When water is heated, it evaporates. The molecules move and vibrate so quickly that they escape into the atmosphere as molecules of water vapor. ... Once water evaporates, it also helps form clouds

Explanation:

2,4-DNP is negative: aldehyde and ketone absent

Chromic acid is negative: alcohol absent.

KMnO4 test negative: alkene absent

The only positive result is for Fe(OH)2.

Nitro group-containing compounds react with ferrous hydroxide to give amine and ferric hydroxide red ppt. Hence given compound contains the nitro group (-NO2).

Answer:

Cost.  

Weapons Proliferation Risk.  

Meltdown Risk.  

Mining Lung Cancer Risk.

Explanation:

Hope this helped!!!

Answer:

605.6mg of quinine

Explanation:

Based on Lambert-Beer's law, the intensity of an optical measurement is directely proportional to its concentration.

Unknown concentration gives a reading of 327

100 ppm gives 180 of intensity

The concentration of the diluted quinine tablet is:

327 * (100ppm / 180) = 181.67 ppm. The final dilution

The concentration of the first diluted solution is:

181.67 ppm * (100.0mL / 15mL) = 1211ppm

ppm could be defined as mass of solute (In this case of quinine) in mg per liter of solution. That is:

1211mg / L

As the tablet was diluted to 500mL = 0.5L, the mass of the quinine is:

0.5L * (1211mg / L) =

Explanation:

Carbon has the ability to form long chains of carbon atoms as well as ringed compounds by continuously bonding to itself. This covalent bonds may be single, double, or triple. Carbon forms covalent bonds easily with other elements, especially hydrogen, oxygen, nitrogen, halogens, and a variety of nonmetals.

Answer:

40 and 10

Explanation:

40 plus 10 is 50 40 minus 10 is 30

Answer:

40 and 10

Explanation:

Answer:

pH= 4; pOH= 10

Explanation:

HCl is a strong acid and therefore dissociates completely in a solution of water via HCl + H2O --> Cl- + H3O+.

Because it is a strong acid, [HCl] = [H3O+].

[HCl]= [H3O+]= (0.005 mol)/(50L)= 1.0 x 10^-4

pH= -log[H3O+]

pH= -log(1.0 x 10^-4)= 4

pH + pOH = 14

4 + pOH = 14

pOH= 10

Answer:

[tex]\color{Blue}\huge\boxed{Answer} [/tex]

Water moves through the hydrosphere in a cycle. Water collects in clouds, then falls to Earth in the form of rain or snow. This water collects in rivers, lakes and oceans. Then it evaporates into the atmosphere to start the cycle all over again.

Answer:

10.5 g

Explanation:

Step 1: Given data

Step 2: Calculate the moles of solute (n)

Molarity is equal to the moles of solute divided by the liters of solution.

M = n/V

n = M × V

n = 0.243 mol/L × 0.580 L = 0.141 mol

Step 3: Calculate the mass corresponding to 0.141 moles of KCl

The molar mass of KCl is 74.55 g/mol.

0.141 mol × 74.55 g/mol = 10.5 g

Answer:   First we need to know how many moles of each reactant there are.

C6H12O6 :         25g/180.06g/mol=0.1388mol

O2:                    40g/32g/mol=1.25mol

The equation tells us we need 6 moles of O2 for every 1 mole of Glucose.

6 x 0.1388 = 0.8328

So, we have more O2 then needed – it is in excess.

Glucose is the limiting reagent – we use this for the calculation.

The equation tells us we make 6 moles of CO2 for every 1 mole of Glucose

So, we make 0,8328 moles of Carbon Dioxide

Explanation:

1.267 x 10 ^ 24 is the total number of atoms

Answer:

a. Aqueous

Explanation:

Took the test

Answer:

B.

Our pupils contract and expand depending on the amount of light at any given time in order to avoid being blinded and to see better in the darkness.

Answer:

In humans, there are two major processes used to convert glucose into energy. cellular respiration or aerobic respiration is one of these processes that take place in presence of oxygen that converts glucose into CO2.

The other process is lactic acid fermentation occurs in muscles in case of depletion of oxygen which converts glucose into lactic acid.

The third process is alcoholic fermentation does not take place in humans and occurs in yeast and some bacteria where they produce ethanol.

Humans cannot use alcoholic fermentation in their own body ferment as there is no genetic information in us to do so as it has encoded in yeast and bacteria.

Answer:

A five-sided shape is called a pentagon.

Explanation:

Answered by NONE other than the ONE & ONLY #QUEEN herself aka #DRIPPQUEENMO!!!

Hope this helped!!!

Answer:

a pentagon

Explanation:

I remember that a pentagon has 5 sides

Answer:

a. pH = 2.04

b. pH = 3.85

c. pH = 8.06

d. pH = 11.56

Explanation:

The nitrous acid is a weak acid (Ka = 5.6x10⁻⁴) that reacts with NaOH as follows:

HNO₂ + NaOH → NaNO₂(aq) + H₂O(l)

a. At the beginning there is just a solution of 0.12M HNO₂. As Ka is:

Ka = [H⁺] [NO₂⁻] / [HNO₂]

Where [H⁺] and [NO₂⁻] ions comes from the same equilibrium ([H⁺] = [NO₂⁻] = X):

5.6x10⁻⁴ = X² / 0.15M

8.4x10⁻⁵ = X²

X = [H⁺] = 9.165x10⁻³M

As pH = -log [H⁺]

b. At this point we have HNO₂ and NaNO₂ (The weak acid and the conjugate base), a buffer. The pH of a buffer is obtained using H-H equation:

pH = pKa + log [NaNO₂] / [HNO₂]

Where pH is the pH of the buffer,

pKa is -log Ka = 3.25

And [NaNO₂] [HNO₂] could be taken as the moles of each compound.

The initial moles of HNO₂ are:

0.100L * (0.15mol / L) = 0.015moles

The moles of base added are:

0.0800L * (0.15mol / L) = 0.012moles

The moles of base added = Moles of NaNO₂ produced = 0.012moles.

And the moles of HNO₂ that remains are:

0.015moles - 0.012moles = 0.003moles

Replacing in H-H equation:

pH = 3.25 + log [0.012moles] / [0.003moles]

c. At equivalence point all HNO2 reacts producing NaNO₂. The volume added of NaOH must be 100mL. That means the concentration of the NaNO₂ is:

0.15M / 2 = 0.075M

The NaNO₂ is in equilibrium with water as follows:

NaNO₂(aq) + H₂O(l) ⇄ HNO₂(aq) + OH⁻(aq) + Na⁺

The equilibrium constant, kb, is:

Kb = Kw/Ka = 1x10⁻¹⁴ / 5.6x10⁻⁴ = 1.79x10⁻¹¹ = [OH⁻] [HNO₂] / [NaNO₂]

Where [OH⁻] = [HNO₂] = x

[NaNO₂] = 0.075M

1.79x10⁻¹¹ = [X] [X] / [0.075M]

1.34x10⁻¹² = X²

X = 1.16x10⁻⁶M = [OH⁻]

pOH = -log [OH-] = 5.94

pH = 14-pOH

d. At this point, 5mL of NaOH are added in excess, the moles are:

5mL = 5x10⁻³L * (0.15mol / L) =7.5x10⁻⁴moles NaOH

In 100mL + 105mL = 205mL = 0.205L. [NaOH] = 7.5x10⁻⁴moles NaOH / 0.205L =

3.66x10⁻³M = [OH⁻]

pOH = 2.44

pH = 14 - pOH

Answer:

dfgh

Explanation:

Answer:

There are 1.8021⋅1024 molecules of CH4 in 48 grams of CH4 .

Explanation:

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Answer:

[tex]V_2=9.20L[/tex]

Explanation:

Hello there!

In this case, according to the given STP (standard pressure and temperature), it is possible for us to realize that the equation to use here is the Avogadro's law as a directly proportional relationship between moles and volume:

[tex]\frac{V_2}{n_2}= \frac{V_1}{n_1}[/tex]

In such a way, given the initial volume and both initial and final moles, we can easily compute the final volume as shown below:

[tex]V_2= \frac{V_1n_2}{n_1} \\\\V_2=\frac{5.36L*6.0mol}{3.5mol}\\\\V_2=9.20L[/tex]

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Answer:

Chemical energy

Explanation:

By the use of electrons and protons from water

Answer:

chemical energy

Explanation:

Photosynthesis is the process by which organisms that contain the pigment chlorophyll convert light energy into chemical energy which can be stored in the molecular bonds of organic molecules (e.g., sugars). Photosynthesis powers almost all trophic chains and food webs on the Earth.

Answer: I believe the answer is A, heat moves from warmer objects to cooler objects. I know for sure it isn’t C or D though so A

The heat is transferred from one object to another as heat moves from warmer objects to cooler objects. The correct option is A.

There are three ways to transfer heat. They are conduction, convection, and radiation. Heat travels from one body to another body. If the temperature of two objects is different, then the heat travels from higher temperature to lower temperature.

Conduction is the transfer of energy when two objects ate in contact with each other. Convection is a transfer between object and environment. Radiation is when transferred by emission of electromagnetic radiation.

Thus, the correct option is A. Heat moves from warmer objects to cooler objects.

Learn more about the transfer of heat, here:

https://brainly.com/question/13433948

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Answer:

Molarity=Moles of solute/volume of solution in Litres

Simply imputing your values

you have

0.75/65

0.0115M.

Answer:

A decrease in temperature decreases the number of collisions between molecules . The reaction rate will  decrease

Explanation:

Answer:

Show a picture

Explanation:

Answer:

I₂CL₆

Explanation:

Answer12C1

Explanation: