again with the chemistry questions all help is appreciated :’)

Answer:

organisms in rain water and the number of organisms in pond water because the dependant variable never changes

Explanation:

because the dependant variable never changes

When 1.0 mole of ZnO(s) decomposes, the standard enthalpy change, ΔH, is 350 kJ/mol. This tells us that the decomposition of ZnO is endothermic (A).

The standard enthalpy change, ΔH, refers to the energy change that occurs when one mole of a substance reacts or undergoes a physical change under standard conditions (25°C and 1 atm). This enthalpy change is often associated with reactions or physical changes that are exothermic or endothermic.

An endothermic reaction is a type of chemical reaction in which energy is absorbed from the surroundings in the form of heat. This results in an increase in the internal energy of the system as the reactants are converted to products, and the surroundings become colder. In contrast, exothermic reactions release heat to the surroundings.

Hence, the correct answer is Option A.

Learn more about endothermic reaction here: https://brainly.com/question/30133682

#SPJ11

Answer:

false

Explanation:

salt water cannot be classified as a substance because it's composition can vary

Answer:

Explanation:The buffer is a mixture of ammonia (NH3) and ammonium (NH4+). ... Since ammonia (NH3) is a weak base, it will have a pH above 7 and since ammonium (NH4+) is a weak acid, it will have a pH below 7. Ammonia (NH3) is a weak base and ammonium (NH4+) is a weak acid. Ammonia (NH3) is the conjugate base of ammonium (NH4+).

Answer:

Logan could explain the lower mass by explaining that the reaction between hydrochloric acid and magnesium produces hydrogen gas, which escapes and therefore is not included in the final combined mass measurement. The reaction is:HCl + Mg → MgCl2 + H2Since the hydrogen gas has mass, its escape from the reaction vessel explains the decrease in the combined mass of the reactants after the reaction.

In NH2Br, there are a total of 6 bonds. To determine the number of polar and non-polar bonds, we need to examine the electronegativity difference between the atoms involved in each bond.

In NH2Br, the central atom is nitrogen (N), and it is bonded to two hydrogen atoms (H) and one bromine atom (Br).

The N-H bonds are polar because nitrogen is more electronegative than hydrogen, creating a partial negative charge on nitrogen and a partial positive charge on hydrogen.

The N-Br bond is also polar because nitrogen is more electronegative than bromine, resulting in a partial negative charge on nitrogen and a partial positive charge on bromine.

Therefore, in NH2Br, there are 3 polar bonds (N-H, N-H, N-Br) and 3 non-polar bonds (H-H, H-H, Br-H).

To summarize:

Total bonds: 6

Polar bonds: 3 (N-H, N-H, N-Br)

Non-polar bonds: 3 (H-H, H-H, Br-H)

It's important to note that the polarity of a bond is determined by the electronegativity difference between the atoms involved. If the electronegativity difference is significant, the bond is considered polar; otherwise, it is considered non-polar.

To know more about bond click this link -

brainly.com/question/30508122

#SPJ11

The measured Kc is different from the calculated Kc, the system is not at equilibrium. There is either too much hydrogen iodide and/or too little hydrogen and/or iodine in the cylinder.

To determine whether the system is at equilibrium, we can use the equilibrium constant expression for the reaction;

H₂(g) + I₂(g) ⇌ 2HI(g)

The equilibrium constant expression for this reaction is;

Kc = [HI]² / [H₂] [I₂]

We are given the partial pressures of each component in the cylinder, so we can calculate the concentrations using the ideal gas law.

[P] = n/V = (m/M) / V

where P is the partial pressure, n is the number of moles, V is the volume, m is the mass, M is the molar mass, and the square brackets denote concentration.

For hydrogen (H₂)

[P] = n/V = (m/M) / V

[m/M] = [P] x V

[m/M] = 0.127 atm x V / R x T

For iodine (I₂)

[P] = n/V = (m/M) / V

[m/M] = [P] x V

[m/M] = 0.134 atm x V / R x T

For hydrogen iodide (HI)

[P] = n/V = (m/M) / V

[m/M] = [P] x V

[m/M] = 1.055 atm x V / R x T

Switching these expressions into the equilibrium constant expression, we get;

Kc = ([HI]/V)² / ([H₂]/V) x ([I2]/V)

Kc = ([HI]² / V²) / ([H₂] x [I2] / V²)

Put in the values we get:

Kc = [(1.055 atm / V)² / (0.127 atm / V) x (0.134 atm / V)]

Kc = 8.37 atm² / V²

If the system is at equilibrium, the measured concentrations should give the same value for Kc as calculated above. If the measured Kc is different, then the system is not at equilibrium.

Therefore, we can calculate the measured Kc as;

Kc = ([HI]² / V²) / ([H₂] x [I2] / V²)

Kc = [(1.055 atm / V)² / (0.127 atm / V) x (0.134 atm / V)]

Kc = 8.87 atm² / V²

To know more about equilibrium constant here

https://brainly.com/question/10038290

#SPJ4

Wade will need the following two abilities to succeed in the field of radiology:

1. Interpersonal abilities to communicate with patients and make them feel at ease.

2. Technical expertise required to operate machinery and equipment

A radiologist is a specialty physician who employs imaging techniques to diagnose and treat human illness or damage, including x-ray, MRI, CT, ultrasound, and angiography. Radiologists must complete extensive training and testing in order to receive accreditation from the appropriate governing bodies.

A subspecialty of radiology is called interventional radiology (IR). Through tiny incisions in your body, doctors execute minimally invasive surgical operations while also interpreting your medical images in interventional radiology.

To know more about Radiologists visit:

https://brainly.com/question/14617595

#SPJ9

Volume of H₂O produced = (1.8 g) × (1 cm³/g) = 1.8 cm³

Simplifying :

Molar volume of O₂ at STP = 22400 cm³/mol

No. of moles of O₂ liberated = (1120 cm³) / (22400 cm³/mol) = 0.05 mol

According to the given equation, mole ratio H₂O : O₂ = 2 : 1

No. of moles of H₂O produced = (0.05 mol) × 2 = 0.1 mol

Molar mass of H₂O = (1×2 + 16) g/mol = 18 g/mol

Mass of H₂O produced = (0.1 mol) × (18 g/mol) = 1.8 g

Volume of H₂O produced = (1.8 g) × (1 cm³/g) = 1.8 cm³

What happens in the decomposition of hydrogen peroxide?

The decomposition of hydrogen peroxide can be summarized by the chemical equation: which states that two molecules of hydrogen peroxide break down to form two molecules of water and one molecule of oxygen gas, along with heat energy.

Why does hydrogen peroxide decompose quickly?

In many living organisms hydrogen peroxide is a product of metabolism that must be broken down, since in appreciable concentrations it is toxic. The rate of decomposition is increased by the intra-cellular enzyme catalase.

At what temperature does hydrogen peroxide decompose?

Properties. The boiling point of H 2O 2 has been extrapolated as being 150.2 °C (302.4 °F), approximately 50 °C (90 °F) higher than water. In practice, hydrogen peroxide will undergo potentially explosive thermal decomposition if heated to this temperature

Learn more about decomposition of hydrogen peroxide:

brainly.com/question/20418092

#SPJ4

Answer:

Waves carry energy from one place to another.

Because waves carry energy,some waves are used for communication,eg radio and television waves and mobile telephone signals.

Explanation:

i hope it helps

that's my answer

correct me if im wrong

Answer:

Tension, friction, and normal

Explanation:

Answer:

Explanation:

Isotope notation is of the form

A

Z

X

where  

Z

is the atomic number (number of protons),  

A

is the mass number (sum of protons and neutrons), and   X   is the element.

In Carbon- 14 ,   14  is the mass number (sum of protons and neutrons). This is our  A .

Carbon has the atomic symbol   C , and it has  6 protons. This is the atomic number, or  A . Thus, the isotope notation for Carbon- 14  is  14  6  C

Hope this helps!

Explanation:

Answer:

D.) electron spin

Each sublevel is labeled by its principal energy level and sublevel. Electrons are indicated by arrows inside of the circles. An arrow pointing upwards indicates one spin direction, while a downward pointing arrow indicates the other direction

Answer:

0.88g

Explanation:

The reaction equation:

         2NaI  + Cl₂   →    2NaCl  + I₂

Given parameters:

Mass of Sodium iodide = 2.29g

Unknown:

Mass of NaCl = ?

Solution:

To solve this problem, we work from the known to the unknown.

First find the number of NaI from the mass given;

   Number of moles  = \(\frac{mass}{molar mass}\)  

          Molar mass of NaI  = 23 + 126.9  = 149.9g/mol

 Now insert the parameters and solve;

     Number of moles  = \(\frac{2.29}{149.9}\)   = 0.015mol

So;

 From the balanced reaction equation;

            2 moles of NaI produced 2 moles of NaCl

          0.015mole of NaI will produce 0.015mole of NaCl

Therefore;

      Mass  = number of moles x molar mass

      Molar mass of NaCl = 23 + 35.5  = 58.5g/mol

Now;

      Mass of NaCl  = 0.015 x 58.5  = 0.88g

The correct order of increasing size is in each set is:  Li⁺ < Na⁺ < K⁺, Br⁻ < Se²⁻ < Rb⁺, and  N³⁻ < O²⁻ < F⁻.

a. In order of increasing size, the ions in set a are: Li, Na, K. This is because they all have the same charge (+1), but as you move down the periodic table, the atomic radius increases.

b. In order of increasing size, the ions in set b are: Br-, Se2-, Rb. This is because Br- and Se2- have the same charge (-1), but as you move down the periodic table, the atomic radius increases. Rb has a larger atomic radius than Se, which gives it a larger ionic radius.

c. In order of increasing size, the ions in set c are: N3-, O2-, F-. This is because they all have the same charge (-1), but as you move across the periodic table, the atomic radius decreases. F- has the smallest atomic radius, which gives it the smallest ionic radius.

Know more about Atomic Radius here:

https://brainly.com/question/14086621

#SPJ11

Answer: Heyo Kenji Here! Here's your answer- N2(g) → NH4+(aq)

Explanation: Hope this helps!

Have a nice day!
- Kenji ^^

The naturally occurring the element x exists in three isotopic forms. The average atomic weight of x 28.544 amu.

Given that :

x- 28, Abundance % = 67.14 % = 0.6714

The atomic mass = 27.343 amu

x-29, Abundance % = 10.50 % = 0.1050

The atomic mass = 28.889 amu

x- 32, Abundance %  = 22.36 % = 0.2236

The atomic mass = 31.993 amu

The average atomic weight = ( 27.343 × 0.6714 ) + ( 28.889 × 0.1050) +

                                                          ( 31.993 × 0.2236)

                                                 = 18.358 + 3.0333 + 7.153

                                                 = 28.544 amu

Thus, the average atomic weight of naturally occurring element x exists in three isotopic forms 28.544 amu.

To learn more about average atomic weight here

https://brainly.com/question/28013988

#SPJ4

The first step is to write the combustion reaction of hexane:

Now, we can use Avogadro's Number to find the amount of moles of hexane and O2 that are reacting:

Using the stated reaction we can determine the amount of moles of O2 that react with 0.43 moles of hexane:

From this we can conclude that the limiting reactant is the O2, which means that we have to use the amount of O2 to make the calculations. Use this amount and the stoichiometric ratio of O2 and H2O to find the amount of water produced from 1.16moles of oxygen:

Now, we can use Avogadro's number to convert the amount of moles produced to molecules:

It means that 5.12x10^23 molecules of water are produced.

Answer:Particles in plasmas collide more often.

Plasma particles have high kinetic energy (they move quickly).

Plasma particles are far apart.

The ionized particles have no fixed volume

Explanation:

Plasma is the fourth form of matter which has freely moving electrons in it. The substance can be identified as plasma if its particles collide often and are far apart.

Plasma is a type of matter other than solids, liquids, and gas. They have similar properties to that of gas. Plasma particle collides are often like gases as they move freely in space. Like gases that have no definite shape and volume.

The plasma particles have ionic charges, positive and negative resulting in high kinetic energy. This property allows them to show electromagnetism and electrical conductivity.

The ionized particles are due to the high temperature that allows them to have the property of electrical conductivity and compression.

Therefore, the particles of plasma are ionized and have high kinetic energy.

Learn more about plasma here:

https://brainly.com/question/10133920

#SPJ6

Answer:

2C4H10 + 13O2 → 8CO2 + 10H2O

Hope this helps brainleist??

Explanation:

1. The question being asked in the experiment above is, "Will the lotion with the new chemical act as a sunscreen and prevent sunburn?"

2. The hypothesis that is being tested in the experiment described above is, "If the lotion with the new sunscreen chemical (Sun X) is applied, then it will act as a sunscreen and prevent sunburn more effectively than the lotion with the different active sunscreen chemical (Sun Kissed) and the lotion that has all the same ingredients except no active sunscreen chemical.

Yes, the hypothesis is testable and falsifiable. It is testable because it can be tested through the experiment described above. It is falsifiable because it can be proven false if the lotion with the new sunscreen chemical (Sun X) does not prevent sunburn more effectively than the other two lotions.

3. The prediction based on the hypothesis is that the lotion with the new sunscreen chemical (Sun X) will act as a sunscreen and prevent sunburn more effectively than the lotion with the different active sunscreen chemical (Sun Kissed) and the lotion that has all the same ingredients except no active sunscreen chemical.

4. The independent variable in this experiment is the type of lotion being applied to the test subject's arm. This is because the researcher can manipulate the type of lotion being applied.

5. The dependent variable in this experiment is the amount of redness measured on the test subject's arm. This is because the amount of redness depends on the type of lotion being applied.

6. The experimental group is the group of patients that are given the lotion with the new sunscreen chemical (Sun X). This is because this group is being tested to determine if the new chemical acts as a sunscreen and prevents sunburn.

7. The negative control group is the group of patients that are given the lotion that has all the same ingredients except no active sunscreen chemical. This is because this group is being tested to ensure that any differences observed between the other two groups are due to the presence or absence of the active sunscreen chemical, rather than any other factor.

8. The positive control group is the group of patients that are given the lotion with the different active sunscreen chemical (Sun Kissed). This is because this group is being tested to ensure that the experiment is able to detect differences in the effectiveness of different sunscreens.

To know more about Sunscreens visit:

https://brainly.com/question/20448560

#SPJ11

Answer:

1. V2.

2. 299K.

3. 451K

4. 0.25 x 451 = V2 x 299

Explanation:

1. The data obtained from the question include:

Initial volume (V1) = 0.25mL

Initial temperature (T1) = 26°C

Final temperature (T2) = 178°C

Final volume (V2) =.?

2. Conversion from celsius to Kelvin temperature.

T(K) = T (°C) + 273

Initial temperature (T1) = 26°C

Initial temperature (T1) = 26°C + 273 = 299K

3. Conversion from celsius to Kelvin temperature.

T(K) = T (°C) + 273

Final temperature (T2) = 178°C

Final temperature (T1) = 178°C + 273 = 451K

4. Initial volume (V1) = 0.25mL

Initial temperature (T1) = 299K

Final temperature (T2) = 451K

Final volume (V2) =.?

V1 x T2 = V2 x T1

0.25 x 451 = V2 x 299

Answer:

Cassiterite is an ore of Sn.It is also called tinstone and has molecular formula of SnO

2 . It is heavy, metallic, hard tin dioxide that is the major ore of tin. It is colourless when pure, but brown or black when iron impurities are present.

Answer:

7:4

Explanation:

O2 : NO2

7 : 4

hope this helps :)

Answer:

One of the most notable characteristics of a mixture is that it does not have a fixed composition. Water, a compound, always has 11.2 percent hydrogen and 88.8 percent oxygen by weight. Brass is a mixture because it has varying amounts of copper and zinc. One type of brass may contain as much as 45 percent zinc, while another type may contain around 10 percent zinc. Mixtures may also have changing properties depending on their composition. The boiling point of a mixture of alcohol and water varies based on how much alcohol is in the mixture.

Hope this helps :)

Answer:  C... Because Zinc is made of only one type of atoms.

Explanation: All elements are made of one type of atom. Pure gold is made out of only gold atoms, silver out of only silver atoms, etc.