Which statement best describes a heart attack?

A. The heart muscle tissues get too much oxygen

B. The heart muscle tissue get too little oxygen

C. The heart muscle tissue get the normal average amount of oxygen

D. None of the above

A higher density water will be obtained in lower temperature water.

Density is the fluid property that describes the amount of solutes that dissolves in a given volume of the fluid.

Density of a fluid is calculated by taking the ratio of mass to volume of the fluid.

[tex]\rho = \frac{m}{v}[/tex]

When the temperature of the water is low, more mass of the water is obtained while a high temperature evaporates the liquid.

Thus, a higher density water will be obtained in lower temperature water.

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Answer:

See explanation

Explanation:

The percentage by mass of oxygen is defined as;

Mass of oxygen/ molar mass of the compound * 100/1

The average percentage by mass of oxygen = 38.933 + 38.940 + 38.871 + 38.892 + 38.900/5

The average percentage by mass of oxygen = 38.907

Percentage Error  = (|accepted value – experimental value| \ accepted value) x 100%

Percentage Error  = 39.13 - 38.907 / 39.13 * 100

Percentage Error  = 0.57%

Answer:

0.263 mol

Explanation:

K2SO4 - potassium sulfate

Molar mass (K2SO4) = 2*39.0983 + 32.065 + 4*15.9994 =

= 174.2592≈174.26 g/mol

45.8 g * 1 mol/174.26 g = 0.263 mol

Answer: the electrostatic potential energy is -3.26 × 10⁻¹⁸ J

Explanation:

Given the data in the question;

I think the value of electrostatic potential energy of calcium sulfide CaS formed will be less(more negative) than KCl because the Ca2+ and S2- ions has more charge that is +2 and -2 respectively when compared to Kcl which has +1 and -1 charge.so it will be more negative.

radius = r[tex]_{ca+2}[/tex] + r[tex]_{s-2}[/tex] = 100 + 184 = 284 pm = 2.84 × 10⁻¹⁰ m

we know that; k = 2.31 × 10⁻²⁸ J

q1 = 2  ( charge on Ca⁺² )

q2 = -2( charge on S⁻²)

so

Ep = k × q1q2/r

so we substitute

Ep = 2.31 × 10⁻²⁸ × (+2×-2) / 2.84 × 10⁻¹⁰

Ep = (2.31 × 10⁻²⁸ × -4) / 2.84 × 10⁻¹⁰

Ep = -9.24 × 10⁻²⁸ / 2.84 × 10⁻¹⁰

Ep = -3.26 × 10⁻¹⁸ J

Therefore, the electrostatic potential energy is -3.26 × 10⁻¹⁸ J

Based on the data provided, the electrostatic potential energy is -3.26 × 10⁻¹⁸ J

The electrostatic potential energy is the work done in moving the charge from infinity to that point against the electric field.

The electrostatic potential energy between any two charges q1, q2 separated by distance r is derived from Coulomb’s law and mathematically given as:

where

From the data provided:

ionic radii of Ca2+ r1 = 100 pm

ionic radii of S2– = 184 pm.

Chargeon Ca2+ = +2

Charge on S2_ = -2

From the data above, it most likely that the value of electrostatic potential energy of calcium sulfide CaS formed will be less(more negative) than KCl because the Ca2+ and S2- ions has a greater charge of +2 and -2 respectively compared to Kcl which has +1 and -1 charge.

Calculating the electrostatic potential energy, Ep:

radius = r1 + r2 = 100 + 184 = 284 pm

r = 2.84 × 10⁻¹⁰ m

k = 2.31 × 10⁻²⁸ J

q1 = 2  ( charge on Ca⁺² )

q2 = -2( charge on S⁻²)

Then:

Ep = k × q1q2/r

Substituting the values above in the equation:

Ep = 2.31 × 10⁻²⁸ × (+2 ×-2) / 2.84 × 10⁻¹⁰

Ep = (2.31 × 10⁻²⁸ × -4) / 2.84 × 10⁻¹⁰

Ep = -9.24 × 10⁻²⁸ / 2.84 × 10⁻¹⁰

Ep = -3.26 × 10⁻¹⁸ J

Therefore, the electrostatic potential energy is -3.26 × 10⁻¹⁸ J.

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Answer:

true

Explanation:

Prophase is the first stage in mitosis, occurring after the conclusion of the G2 portion of interphase. During prophase, the parent cell chromosomes which were duplicated during S phase condense and become thousands of times more compact than they were during interphase.

Answer:

the answer to this question is A H202

Answer:

Hello your question is poorly written hence i will give you a more general answer

answer :  The reason why it is desirable to use an excess of barium ion in the precipitation is to form the compound needed,

Explanation:

Natural Precipitation occurs when condensed atmospheric water vapor falls due to the gravitational pull exerted on it by the clouds. precipitation can be in various forms like ; rain , ice pellets and snow . e.t.c

Hence the reason why it is desirable to use an excess of barium ion in the precipitation is to form the compound needed,

Also in order to form the precipitation, we will also add excess of barium ion which will help form the required precipitate and also  filter out the mass of Sulphate.

In the first box, you should draw a chicken. In the second box, you should draw a cow or a horse.

I hope it helps you!!!! :D

[ pls mark me brainliest i need one more to rank up tysm if u do ]

Answer:

MM = 225.11 g/mol

Explanation:

In this case, let's analyze the data.

We have a 15.2 mg of an unknown electrolyte in 150 mL of solution. The osmotic pressure is 8.44 Torr, and we want the molecular mass of the unknown.

The osmotic pressure can be calculated using the following expression:

π = CRT   (1)    

π: osmotic pressure (8.44 Torr * 1 atm / 760 Torr = 0.011 atm)

C: Concentration of the unknown in the solution

R: universal constant of gases (0.082 L atm / K mol)

T: temperature in Kelvin (25 + 273 = 298 K)

From this expression, we can either solve for C, and then use another expression to calculate the molecular mass, or we can just replace the expressions in the above formula, to get the direct molecular mass. In this case, we'll follow the second method.

Concentration or molarity of a substance can be calculated using:

C = moles / V  (2)

And moles can be calculated using this expression:

moles = m / MM   (3)

Replacing (3) in (2), and then in (1) we have:

C = m / MM * V

π = m * RT / MM * V   (4)

and now, we can solve for MM:

MM = mRT / π V  (5)

Now, we just need to replace the given data into the above expression to get the value of the molecular mass:

MM = (15.2 / 1000) * 0.082 * 298 / 0.011 * 0.150

Hope this helps

Answer:

11.7

Explanation:

The pH is the negative logarithm of the concentration of H+ ions. If the concentration is 2×10-¹² the the pH will be -log(2×10-¹²) which is 11.698 which can be round up to 11.7.

Answer:

N(Au) = 1,20 × 10²²

Explanation:

1) n(Au) = m ÷ M = 4.60 g ÷ 197 g/mol = 0,02 mol

2) N(Au) = n(Au) × N(a) = 0,02 × 6.02*10²³ = 1,20 × 10²²

Answer:

0.389 M

Explanation:

From the question given above, the following data were obtained:

Mass of CuCl₂ = 78.5 g

Volume of solution = 1.50 L

Molarity of CuCl₂ =?

Next, we shall determine number of mole in 78.5 g of CuCl₂. This can be obtained as follow:

Molar mass of CuCl₂ = 63.5 + (35.5×2)

= 63.5 + 71

= 134.5 g/mol

Mass of CuCl₂ = 78.5 g

Number of mole of CuCl₂ =?

Mole = mass / Molar mass

Number of mole of CuCl₂ = 78.5 / 134.5

Number of mole of CuCl₂ = 0.584 mole

Finally, we shall determine the molarity of the solution. This can be obtained as follow:

Number of mole of CuCl₂ = 0.584 mole

Volume of solution = 1.50 L

Molarity of CuCl₂ =?

Molarity = mole / Volume

Molarity of CuCl₂ = 0.584 / 1.50

Molarity of CuCl₂ = 0.389 M

The molarity of a solution that contains 78.5 g of copper(II) chloride in 1.50 L of solution is 0.389M.

The molarity of a solution can be calculated

From the question given above, the following data were obtained:

Next, we shall determine number of moles in 78.5g of CuCl₂. This can be obtained as follow:

Molar mass of CuCl₂ = 63.5 + (35.5×2)

= 63.5 + 71

= 134.5 g/mol

Mass of CuCl₂ = 78.5g

Number of mole of CuCl₂ = 78.5 / 134.5

Number of mole of CuCl₂ = 0.584 moles

The determine the molarity of the solution. This can be obtained as follow:

Molarity = mole / Volume

Molarity of CuCl₂ = 0.584 / 1.50

Molarity of CuCl₂ = 0.389M

Therefore, molarity of a solution that contains 78.5 g of copper(II) chloride in 1.50 L of solution is 0.389M.

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Explanation:

i believe this is right. my bad if its not

Answer:

The total change in enthalpy for the reaction is - 81533.6 J/mol

Explanation:

Given the data in the question;

Reaction;

HCl + NaOH → NaCl + H₂O

Where initial temperature is 21.2 °C and final temperature is 28.0 °C. Ccal is 1234.28 J

Moles of NaOH  = 50.mL × 1.00 M = 50.0 mmol = 0.0500 mol

Moles of HCl = 50.mL × 1.00 M = 50.0 mmol = 0.0500 mol

so, 0.0500 moles of H₂O produced

Volume of solution = 50.mL  +  50.mL  = 100.0 mL

Mass of solution m = volume × density = 100.0mL × 1.0 g/mL = 100 g

now ,

Heat energy of Solution q= (mass × specific heat capacity × temp Δ) + Cal

we know that; The specific heat of water(H₂O) is 4.18 J/g°C.

so we substitute

q_soln = (100g × 4.18 × ( 28.0 °C - 21.2 °C) ) + 1234.28

q_soln = 2842.4 + 1234.28

q_soln = 4076.68 J

Enthalpy change for the neutralization is ΔH[tex]_{neutralization}[/tex]

ΔH[tex]_{neutralization}[/tex] = -q_soln / mole of water produced

so we substitute

ΔH[tex]_{neutralization}[/tex] = -( 4076.68 J ) / 0.0500 mol  

ΔH[tex]_{neutralization}[/tex] = - 81533.6 J/mol

Therefore, the total change in enthalpy for the reaction is - 81533.6 J/mol

Answer:

the enantiomeric excess of the mixture is 40%

Explanation:

The computation of the enantiomeric excess of the mixture is shown below:

As we know that

[tex]= |\frac{R - S}{R + S} |\times 100\\\\= |\frac{70 - 30}{70 + 30}| \times 100\\\\= 40\%[/tex]

Hence, the enantiomeric excess of the mixture is 40%

Answer:0

.63

Explanation:

Answer:

96.09 g/mol

Explanation:

Answer:

See Down

Explanation:

2Al2O3 = 4Al + 3O2 (Decomposition)

31.5/101.961g = 0.3089mol

(0.3089mol/2) * 4 = 0.61788 mole of Al

0.61788 mole * 6.022x10^23 atoms/mol = Your answer

Answer:

im absoulutely positive it is C

Answer:

The independent and dependent variable for the following are as follows:

a. Temperature and amount of dissolved oxygen

b. pH and SO2 solubility/amount

c. H2SO4 concentration and voltage output/performance of battery

Explanation:

In an experiment;

- Independent variable is the variable that the experimenter manipulates or changes in order to get a measurable response.

- Dependent variable is the variable that the experimenter measures based on its response to changes made to the independent variable.

A). In this experiment, a student is trying to investigate the amount of dissolved oxygen in a local pond in response to changes in temperature. Hence, the independent variable is the TEMPERATURE while the dependent variable is the AMOUNT OF DISSOLVED OXYGEN.

B). In this experiment, a wine producer would like to explore if pH affects the solubility of SO2 in the wine by measuring the amount of SO2 in the wine solution over a range of pH values. Hence, the independent variable is the pH while the dependent variable is the SO2 SOLUBILITY OR AMOUNT.

C). In this experiment, a researcher wishes to determine the optimal H2SO4 concentration for the best performance of the battery, as measured by the voltage output. Hence, the independent variable is the CONCENTRATION OF H2SO4 while the dependent variable is the VOLTAGE OUTPUT or PERFORMANCE of the battery.

Answer:

mole ratio, which is equivalent to a 1;1 mole ratio, to a gram ratio. This means that when the reaction consumes 84.03 g of carbon monoxide, it should theoretically produce 132.03 g of carbon dioxide. Use this gram ratio to calculate the theoretical yield for your reaction.

Explanation:

Answer:

particles

atoms

broken

isotope

conductors

electricity

element

combined

Answer:

Ionic Substance is....

Explanation:

In chemistry, an ionic compound is a chemical compound composed of ions held together by electrostatic forces termed ionic bonding. The compound is neutral overall, but consists of positively charged ions called cations and negatively charged ions called anions.