what is the Curie used to measure​

Answer: Since k2 corresponds to 64 hours, the time for the milk to sour at 40 C is 64 h / 9.38 = 6.8 hours.

Explanation:

At temperature T1, the Arrhenius Equation is:

k1 = Ae^(-Ea/RT1).

An equivalent equation can be written at T2:

k2 = Ae^(-Ea/RT2).

If these equations are divided, then A cancels:

k1/k2 = e^(-Ea/RT1)/e^(-Ea/RT2)

Taking the natural log:

ln(k1/k2) = (Ea/RT2)-(Ea/RT1);

or:

ln(k1/k2) = (Ea/R)(1/T2 - 1/T1)

We can infer from the question that the milk sours 3 times as fast at the higher temperature (let's call it T1), so we can arbitrarily call k2 = 1 and k1 = 3.

a) Substitute:

ln(3) =  (Ea/R)(1/276.15 K - 1/293.15 K).

We get Ea/R = 5231.6. Multiply this by whatever value of R you choose to get Ea in your favorite energy unit. Remember the sig figs.

b) Again, let's let the lower temperature = T2, since we have defined k2 = 1:

ln(k1) = (5231.6)(1/276.15 K - 1/313.15);

ln(k1) = 2.24, so k1 = 9.38.

Since k2 corresponds to 64 hours, the time for the milk to sour at 40 C is 64 h / 9.38 = 6.8 hours.

Answer:

NaF, CaBr2, MgO

Explanation:

Hi! For this problem, you are going to want to look at the charges of the elements in order to write their formulas.

NaF: Na has a charge of +1 and F has a charge of -1. This means that they have a 1:1 ratio and the formula is written as such - NaF.

CaBr2: Ca has a charge of +2 and Br has a charge of -1. For this problem you want to make sure that their formal charge (the charge of the entire molecule) equals 0. This means that the negative charges need to equal the positive charges. Looking at this, you are going to need to Br ions with a charge of -1 to equal one Ca ion with a charge of +2 - CaBr2.

MgO: Mg has a charge of +2 and O has a charge of -2. This means that they have a 2:2 ratio which simplifies to a 1:1 ratio and the formula is written as such - MgO.

Hope this helps!

Answer:

Force F = 20N .

Mass m = 2.0 kg

Initial velocity u = 0

acceleration, a = 10m/s  

2

t = 1 sec.

Now Refer to the attachment, See the free body diagram of the block.

Force works on the block:-

Weight, W = mg

W = 2 × 10

W = 20N (which is Downward)  

Normal force N = mg cos37

N = 20 × 0.80  

N = 16 N. (perpendicular & upward to the plane )

Here Applied Force, P = 20N (which is down along the plane)

Now For Final Speed, We know the formula:-

v = u + at

v = 0 + 10 × 1

v = 10 m/s

the Distance travelled s = ut + 0.5 at×t

s = 0 + 0.5 ×10×1×1

s = 5 m.

Now,

(a)     So work done by the force of gravity in 1 sec. = F × d

             ⇒20 N × 5m      

             ⇒100 J.

(b) Here the weight act as downward, so distance travelled in downward.

             ⇒5 × sin37

             ⇒5 × 0.6  

             ⇒3 m.

so work done by gravity,

               ⇒20 N × 3 m

              ⇒60 J.

(c) Now, work done by all the forces  

               ⇒change in Kinetic energy

  ⇒

2

1  m(v2

−u  2

)

⇒0.5×2.0×(10  2

−0  2  )

⇒ 100 J.

⇒W.D by frictional force  

                 = work was done by all forces -( work was done by Normal force + work done by applied force + work done by gravity )  

                 = 100 J - (100 + 60 +0 )

                 = 100 - 1

     Hope this helps you≅        

Answer:

Coefficients represents no of moles while subscripts represent no of atoms.

Answer:

Coefficients came before formula . Example = 4CO means there are 4 molecules of carbonmonooxide.

Subscripts came after and below the formula . Example = Oxygen gas in which 2 is a subscript which means there are 2 atoms of Oxygen in 1 molecule of Oxygen i.e. oxygen gas

Answer: Peer-reviewed journal article is the most useful because the information in them had been carefully scrutinized and aproved by people who are experts in that particular field.

Answer:

a.Neon

b.carbon

c potassium

Answer:

Suns gravity

Explanation:

Answer: 2021

B

The Sun's gravity

Explanation: Just took the big test

Answer:

vector quantity

Explanation: Brainliest pls

Answer:

4.63 mol

Explanation:

Step 1: Write the balanced complete combustion reaction of acetylene

2 C₂H₂(g) + 5 O₂(g) ⟶ 4 CO₂(g) + 2 H₂O(g)

Step 2: Establish the appropriate molar ratio

According to the balanced equation, the molar ratio of C₂H₂ to O₂ is 2:5.

Step 3: Calculate the number of moles of O₂ needed to react with 1.85 moles of C₂H₂

We will use the stoichiometric molar ratio.

1.85 mol C₂H₂ × (5 mol O₂/2 mol C₂H₂) = 4.63 mol O₂

The statement that describes a physical change is a sculptor casts a statue in molten bronze and allows it to harden. The correct option is C.

"A physical change is one that simply affects the physical nature of the substance." Usually, increasing the temperature or applying pressure, both, will cause a physical change. In other words, physical changes are reversible.

All the other options like rusting of iron bolts on a bridge is a chemical change when iron reacts with oxygen in the air, it gets rust.

Similarly, silver cups exposed to air react with air is a chemical change, and option d, silver off magnesium that creates light, is also a chemical change.

Thus, the correct option is C. A sculptor casts a statue in molten bronze and allows it to harden.

To learn more about physical changes, refer to the below link:

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Answer:

The phosphorus ylide reacts with the aldehyde or ketone to make an oxaphosphetane.

Explanation:

The Wittig reaction is a reaction that occurs between a phosphorus ylide and an aldehyde or ketone. The final products are an alkene and triphenyl phosphine oxide.

The first step in the reaction is the attack of the phosphorus ylide on the aldehyde or ketone. This is followed by attack of oxygen on phosphorus to form a [2+2] cycloaddition product (oxaphosphetane)  which  decomposes to form the alkene and triphenylphosphine oxide.

Answer: 1.38

Explanation:

Gay-Lussac's Law: This law states that pressure is directly proportional to the temperature of the gas at constant volume and number of moles.

[tex]P\propto T[/tex]     (At constant volume and number of moles)

[tex]\frac{P_1}{T_1}=\frac{P_2}{T_2}[/tex]

where,

[tex]P_1[/tex] = initial pressure of gas  = 841 mm Hg

[tex]P_2[/tex] = final pressure of gas  = ?

[tex]T_1[/tex] = initial temperature of gas  =[tex]14.7^0C=(14.7+273)K=287.7K[/tex]  

[tex]T_2[/tex] = final temperature of gas = [tex]84.7^0C=(84.7+273)K=357.7K[/tex]  

[tex]\frac{841}{287.7}=\frac{P_2}{357.7}[/tex]

[tex]P_2=1045.6mm Hg=1.38atm[/tex]    ( 760 mm Hg = 1atm )

Thus the final pressure is 1.38

Answer:

x = w/v

General Formulas and Concepts:

Pre-Algebra

Explanation:

Step 1: Define

v = w/x

Step 2: Solve for x

Answer:

exothermic reaction

Explanation:

because it occurs in the presence of heat

There are 1.204 x 10¹⁹ atoms O

The empirical formula is the smallest comparison of atoms of compound forming elements.  

A molecular formula is a formula that shows the number of atomic elements that make up a compound.  

1 mol of molecule Na₂C₂O₄ :

There are 4 mol of O in 1 mol of molecule Na₂C₂O₄

So for 5 x 10⁻⁶ mol Na₂C₂O₄ :

[tex]\tt mol~O=4\times 5.10^{-6}=2.10^{-5}[/tex]

1 mole = 6.02.10²³ particles , so number of atoms O :

[tex]\tt 2\times 10^{-5}\times 6.02\times 10^{23}=1.204\times 10^{19}[/tex]

it is push i think to move the car

Answer:

Either A. Push or B.Pull because the truck is either pushing or pulling the car to move it. So it depends on if it's pushing or pulling the car.

Explanation:

This is an example of #2, conduction.

Conduction is the process where heat energy is transmitted through collisions between atoms or molecules.

Answer:

an electromagnetic wave

Explanation:

Answer:

the answer is b

Explanation:

brcause the gravutational pull on the moon is lower than on earth...

Answer:

Chemistry deals with matter, and there is a tremendous variety of matter in the universe. The behavior of matter depends on the type of elements that are present and on the structure of those elements—how they are connected to make a molecule. In this exercise, you will evaluate some representative models to develop the rules used to classify a compound, to predict the formula of a compound, and to name the compound. This exercise is just the beginning of the work needed to be done to master the rules of writing formulas and nomenclature. Your textbook has tables of the names and formulas of common cations and anions, and discusses the rules of nomenclature in detail. You will need to spend some time with this material, as the formal rules of nomenclature may not be presented in lecture, although they will certainly be used in discussions of Lewis structures and reaction chemistry.

Explanation:

In a covalent compound, valence electrons are shared between the two atoms in the bond. These can be evenly shared (covalent bond) or unevenly shared (polar covalent bond). In an ionic bond, electrons are localized to one of the atoms (giving it an overall negative charge), while the other atom has an overall positive charge. The difference in electronegativity between the two atoms in the bond can help predict whether the bond is likely to be ionic, covalent, or polar covalent, as can the type of atoms involved (metals or non-metals). A bond with two identical atoms is always pure covalent, while a covalent bond with two different atoms is likely to be polar covalent.

Hi

i hope this helps

Answer:

The Greek atom theory

Explanation:

The concept of the Greek atomos theory is an indivisible particle of matter, goes back to ancient Greece and a man named Democritus held that all matter could be subdivided only until some finite particle was reached.

Answer:

1. 0.28M

2. 24mL

3. 0.002295moles of NaOH.

Explanation:

1. The 6.0M HCl solution is diluted from 35mL to 750mL, that is:

750mL / 35mL = 21.43 times

The 6.0M HCl solution is diluted 21.43 times, the final concentration is:

6.0M / 21.43 = 0.28M

2. First, we need to convert grams of CuNO3 to moles and then, as molarity is moles per liter we can solve for volume of solution in liters and convert it to mililiters:

Moles CuNO3 -Molar mass 124.9g/mol:

2.49g * (1mol / 124.9g) = 0.020 moles of CuNO3

Volume is:

0.020 moles * (1L / 0.830mol) = 0.0240L * (1000mL / 1L) = 24mL

3. In 13.5mL = 0.0135L of 0.17M NaOH the moles are:

0.0135L * (0.17mol / L) = 0.002295moles of NaOH

Answer:

2.

a.Sodium bromide

b. Magnesium dichloride

c. Lithium iodide

not sure about 3 or 4 sry

Answer:

The major innovation made from Abacus to the present fifth generation​ is explained below in details.

Explanation:

Industrial Age - 1600

John Napier, a Scottish noble and diplomat consecrated much of his holiday time to the learning of mathematics. He was particularly engrossed in devising methods to aid estimates. His most famous offering was the discovery of logarithms. He listed logarithmic measures on a set of 10 board rods and thus was capable to do multiplication and division by equaling up numbers on the poles. These became recognized as Napier’s Bones.

The equation is balanced. There are 4 aluminium atoms and 6 oxygen atoms on each side.

Answer:

The answer is 'All of the above'

Explanation:

because the hydrogen ions are represented by the symbol H+, they increase the PH value of a solution if less amount is added but they decrease the PH value of a solution if a larger amount of hydrogen ions are added but still they increase the PH value, and of course, they contribute to a solution by a base.

Answer:

Hydrogen ions are represented by H+.

Explanation:

Answer:

Melting point

Explanation:

it's constant temperature at which the bonds of a solid Crystal lattice are broken down by overcoming the attractive forces converting it to liquid

Answer:

B) +2; 6; -2

Explanation:

In order to know what the coordination number is, all we need to do is to count the number of ligands present in the coordination sphere. Coordination number refers to the number of ligands in the coordination sphere of a given complex. The coordination number here is 6.

The counter ion here is 2Na+. It means that the overall charge on the complex must be -2 because the magnitude of charge on the complex ion is exactly balanced by the number of counter ions.

The charge on the metal (x) must now be;

x + 0 + 4(-1) = -2

x - 4 = -2

x = -2 + 4

x = +2

Note that NH3 is designated as zero because it is a neutral molecule. Each NCS^- ion has a charge magnitude of -1.

Answer:

Water from melting snow or rainfall infiltrates into cracks in rocks. ... As this process of freezing and thawing happens repeatedly, the rock begins to weaken and eventually breaks apart into angular fragments.

Explanation:

Water melting from snow or rainfall which infiltrates into cracks in rocks,  this is repeated process of freezing and thawing,  the rock begins to weaken and eventually breaks apart into angular fragments.

A rock can be formed due to the aggregation of mineral constituents in the earth’s crust and  it can be classified is based on different factors like Geological classification, Physical classification, Chemical classification.

Geological classification can be either Sedimentary rock formed by the deposition of sediments by the weathering of pre-existing rocks and it can be carried out by various agents like water, wind, gravity, etc.

Igneous rocks formed  by the  solidification of magma below the earth’s surface which is held together below the earth’s surface and unable to descend, when these magma cools down  and solidifies into igneous rocks.

Learn more about rock layer, here:

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Answer:

-1.82 °C

Explanation:

Step 1: Given data

Step 2: Calculate the molality of the solution

We will use the following expression.

m = mass of solute / molar mass of solute × kg of solvent

m = 33.9 g / 58.44 g/mol × 0.578 kg

m = 1.00 m

Step 3: Calculate the freezing point depression (ΔT)

The freezing point depression is a colligative property that, for a non-dissociated solute, can be calculated using the following expression:

ΔT = Kb × m

ΔT = -1.82 °C/m × 1.00 m

ΔT = -1.82 °C