Which two of the following changes of state involve solids?
Select two (2) answers


A. melting

B. boiling

C. freezing

D. evaporating

What does botanist study?

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Answer:

A Magnet or Magnetic Filtration

Answer:

Magnetic Filtration

Explanation:

That is the answer

Answer:

Bases Do not Change the Color of Blue Litmus.

I'd go with Option C.

Sodium Hydroxide.

Answer:

this is the answer

I hope it helps you although

Answer:

Gain 2, and become negatively charged

Explanation:

A full valence shell, thus stablilized, has 8 electrons, and so it would need two more, and when atoms gain electrons, they become negatively charged because there are now more electrons than protons (and so, when they lose electrons, they become positively charged). Hope this helps! :)

Answer:

the pair of isotopes are b and e

the element with mass no of 19 is C

the element with atomic no 7is D

Explanation:

B and E are isotopes bcos they have the same atomic no, i.e no of protons. They bother have atomic no of 17 BUT have different mass no i.e sum of neutrons and protons.

(b)C is correct because the sum of the protons and neutrons is 19

(c) D because it has 7 protons

Answer:

28/23

Explanation:

28 : 23

this is written as ,

28/23

u can convert into simplest form but in this question u can't so leave it as it is.

Answer:29.9 or 30

Explanation:

Total, 30.38 grams of chlorine gas can be formed from 50.0 grams of sodium chloride through electrolysis.

To calculate the mass of chlorine that can be formed from 50.0g of sodium chloride (NaCl) through electrolysis, we need to consider the balanced chemical equation for the electrolysis of NaCl;

2 NaCl (aq) → 2 Na (s) + Cl₂ (g)

From the balanced equation, we can see that 2 moles of NaCl produce 1 mole of chlorine gas (Cl₂).

Convert given mass of sodium chloride to moles.

Molar mass of NaCl = 22.99 g/mol (Na) + 35.45 g/mol (Cl)

= 58.44 g/mol

Moles of NaCl = 50.0 g / 58.44 g/mol ≈ 0.856 mol

Calculate moles of chlorine gas formed.

From the balanced equation, 2 moles of NaCl produce 1 mole of Cl₂.

Moles of Cl₂ = 0.856 mol / 2 ≈ 0.428 mol

Convert the moles of chlorine gas to mass.

Molar mass of Cl₂ = 2 × 35.45 g/mol

= 70.90 g/mol

Mass of Cl₂ = 0.428 mol × 70.90 g/mol

≈ 30.38 g

So, approximately 30.38 grams of chlorine gas can be formed from 50.0 grams of sodium chloride through electrolysis.

To know more about chlorine gas here

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Answer:

A

Explanation:

(a) distance measured with metre rule or tape rule

    time measured with stopwatch/ stop clock/ timer

    Average speed = total distance / time

(b) (i) decrease in speed

    (ii) Change in speed = a * t

        4.5 m/s

hope this helps......

Answer:

a)22.2°C after adding magnesium

b)17.3°C before adding magnesium

c) 4.9 is change

Answer:

Lesson Summary. A substance is simply a pure form of matter. In other words, a substance is matter than contains only one type of atom or molecule. Pure substances can be further divided into two sub-categories: elements and compounds.

Explanation:

Radhe Radhe❤

Answer:

42,07%and 18,90%

Explanation:

Answer: The oxygen gas has a pressure of 4 atm if my volume decreases to 1 L.

Explanation:

Given: [tex]V_{1}[/tex] = 2 L,        [tex]P_{1}[/tex] = 2 atm

[tex]V_{2}[/tex] = 1 L,          [tex]P_{2}[/tex] = ?

Formula used to calculate the new pressure is as follows.

[tex]P_{1}V_{1} = P_{2}V_{2}[/tex]

Substitute the values into above formula as follows.

[tex]P_{1}V_{1} = P_{2}V_{2}\\2 atm \times 2 L = P_{2} \times 1 L\\P_{2} = 4 atm[/tex]

Thus, we can conclude that the oxygen gas has a pressure of 4 atm if my volume decreases to 1 L.

Answer: The hydronium [tex](H_{3}O^{+})[/tex] concentration of a solution with a pH of 3.60 is 0.56 M.

Explanation:

pH of a substance is the negative logarithm of concentration of hydrogen ions present in it.

It's formula is; pH = - log [tex][H^{+}][/tex]

When pH of a solution is 3.60 then its hydronium or hydrogen ion concentration is calculated as follows.

[tex]pH = - log [H^{+}]\\3.6 = - log [H^{+}]\\concentration of H^{+} = antilog (-3.6)\\= 0.56[/tex]

Thus, we can conclude that the hydronium [tex](H_{3}O^{+})[/tex] concentration of a solution with a pH of 3.60 is 0.56 M.

Answer:

The Bohr Model is very limited in terms of size. Poor spectral predictions are obtained when larger atoms are in question. It cannot predict the relative intensities of spectral lines. It does not explain the Zeeman Effect, when the spectral line is split into several components in the presence of a magnetic field.

Explanation:

Answer:

espero que te ayude ........

Answer:

Organic molecules are important to living things because life is based on the properties of carbon.

Properties of Carbon

Carbon is an important element because it can form four covalent bonds.

Carbon skeletons can vary in length, branching, and ring structure.

The carbon skeletons contain the functional groups that are involved in biochemical

Explanation:

Hope it helps

Explanation:

When a base dissolves in water it is an alkali and makes an alkaline solution.

...

Litmus.

Red Litmus Blue Litmus

Acidic solution Stays red Turns red

Neutral solution Stays red Stays blue

Alkaline solution Turns blue Stays blue

Answer: Because this does not dissolve in water - it forms a barrier on the surface of the unreacted CaCO3 which prevents any further reaction. A small volume of CO2 is produced , but this stops after a short time . Conclusion: H2SO4 cannot be used with CaCO3 to produce CO2 gas .

Explanation:

Answer:

P2 = 1.94 kPa

Explanation:

Given the following data;

Initial pressure = 2.36 kPa

Initial temperature = 62°C

Standard temperature = 0°C

Conversion:

Kelvin = 273 + C

Kelvin = 273 + 62 = 335 K

Kelvin = 273 + 0 = 273 K

To find the final pressure, we would use Gay Lussac's law;

Gay Lussac states that when the volume of an ideal gas is kept constant, the pressure of the gas is directly proportional to the absolute temperature of the gas.

Mathematically, Gay Lussac's law is given by;

[tex] PT = K[/tex]

[tex] \frac{P1}{T1} = \frac{P2}{T2}[/tex]

Making P2 as the subject formula, we have;

[tex] P_{2}= \frac{P1}{T1} * T_{2}[/tex]

[tex] P_{2}= \frac{2.36}{335} * 273 [/tex]

[tex] P_{2}= 0.0071 * 273 [/tex]

P2 = 1.94 kPa

Answer:

Hydrogen bonds

Covalent bonds

Van Der Walls Forces

Ionic Bonding

London Dispersion forces

Metallic bonding

Chemical bonds

Answer:

El Niño is a climate cycle in the Pacific Ocean with a global impact on weather patterns. The cycle begins when warm water in the western tropical Pacific Ocean shifts eastward along the equator toward the coast of South America. Normally, these warm water pools near Indonesia and the Philippines.

Explanation:

Explanation:

a chemical reaction that absorbs energy is known to be endothermic since heat is being taken in by the reaction. The value of the transition state would be 150 because you have to subtract the product's enthalpy and the reactant's enthalpy to obtain it. A positive value for the transition state also corroborates that the reaction is endothermic.

Answer:

0.017 M

Explanation:

The balanced equation for the reaction is given below:

2H₃PO₄ + 3Ba(OH)₂ ⇌ Ba₃(PO₄)₂ + 6H₂O

From the balanced equation above,

The mole ratio of acid, H₃PO₄ (nₐ) = 2

The mole ratio of base, Ba(OH)₂ (n₆) = 3

Finally, we shall determine the concentration of the phosphoric acid, H₃PO₄. This can be obtained as follow:

Volume of acid, H₃PO₄ (Vₐ) = 125 mL

Volume of base, Ba(OH)₂ (V₆) = 63.7 mL

Concentration of base, Ba(OH)₂ (C₆) = 0.050M

Concentration of acid, H₃PO₄ (Cₐ) =?

CₐVₐ / C₆V₆ = nₐ/n₆

Cₐ × 125 / 0.05 × 63.7 = 2/3

Cₐ × 125 / 3.185 = 2/3

Cross multiply

Cₐ × 125 × 3 = 3.185 × 2

Cₐ × 375 = 6.37

Divide both side by 375

Cₐ = 6.37 / 375

Cₐ = 0.017 M

Thus, the concentration of the phosphoric acid, H₃PO₄ is 0.017 M

Answer:

2 L

Explanation:

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

Molarity of LiF = 2 M

Mole of LiF = 4 moles

Volume =?

Molarity of a solution is simply defined as the mole per unit litre of the solution. Mathematically, it is expressed as:

Molarity = mole / Volume

With the above formula, we can obtain the volume of the solution as shown below:

Molarity of LiF = 2 M

Mole of LiF = 4 moles

Volume =?

Molarity = mole / Volume

2 = 4 / volume

Cross multiply

2 × volume = 4

Divide both side by 2

Volume = 4/2

Volume = 2 L

Therefore, the volume of the solution is 2 L.

Answer:

17. 3,101.922

18. 1.2447441822

19. 288,057.12

20. 0.74497354

a) The genotype is Hh. We simply combine the two given letters together to get this genotype.

b) The phenotype is Widow's peak. The uppercase letter is the dominant allele, while the lowercase is recessive. Any presence of the dominant allele (even a single letter) will mean the dominant phenotype will present itself. We can see that HH leads to Widow's peak phenotype, so that applies to Hh as well. Only when there isn't a dominant allele at all, the genotype hh, is when the recessive phenotype will show up.

Explanation:

I. Because an explosion is a very fast exothermic reaction

ll. it depends on the it's particle size