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3 years ago

What are the two kinds of ways matter changes?

1 answer:

4 0

There are two types of change in matter: physical change and chemical change. As the names suggest, a physical change affects a substance's physical properties, and a chemical change affects its chemical properties.

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Answer this for me please I got homework from science and it's confusing me

viktelen [127]

type the question please. The picture is to hard to see

8 0

4 years ago

Indicate which solution in each pair has the lower pH. Your response should be a four letter "word". The first letter should be

JulijaS [17]

Answer:

bcfh

Explanation:

HClO₄ reacts with water thus:

HClO₄ + H₂O → H₃O⁺ + ClO₄⁻

That means HClO₄ produce H₃O⁺ that decreases pH. That means the higher concentration of HClO₄ decreases pH. Thus, lower pH will be:

b) 0.2 M HClO4

The reaction of NaClO₄ is:

NaClO₄ + H₂O → OH⁻ + HClO₄ + Na⁺

The higher concentration of NaClO₄ the higher production of OH⁻ that increase pH, that means the lower concentration of NaClO₄ the lower pH, thus, the answer is:

<em>c) 0.1 M NaClO or</em>

HF reacts with water thus;

HF ⇄ H⁺ + F⁻

The equilibrium constant is:

k = [H⁺] [F⁻] / [HF] = 3,5x10⁻⁴

For HNO₂ equilibrium is:

HNO₂ ⇄ H⁺ + NO₂⁻

k = [H⁺] [NO₂⁻] / [HNO₂] = 4,5x10⁻⁴

As k value is higher for HNO₂, the concentration of H⁺ will be higher in this system doing the HNO₂ with the lower pH.

f) 0.1 M HNO2

NaOH is a strong base that produce OH⁻ that increase pH, pure water is neutral, thus, the lowe pH is:

h) pure water

I hope it helps!

7 0

4 years ago

A) Find the gas speed of ammonia at 25.0 degrees Celsius. ______________

Cloud [144]

a. 661.23 m/s

b. the rate of effusion of Ammonia = 4.5 faster than Silicon tetra bromide

<h3> Further explanation </h3>

Given

T = 25 + 273 = 298 K

Required

a. the gas speed

b. The rate of effusion comparison

Solution

Average velocities of gases can be expressed as root-mean-square averages. (V rms)

$\large {\boxed {\bold {v_ {rms} = \sqrt {\dfrac {3RT} {Mm}}}}$

R = gas constant, T = temperature, Mm = molar mass of the gas particles

From the question

R = 8,314 J / mol K

T = temperature

Mm = molar mass, kg / mol

Molar mass of Ammonia = 17 g/mol = 0.017 kg/mol

$\tt v=\sqrt{\dfrac{3\times 8.314\times 298}{0.017} }=661.23~m/s$

b. the effusion rates of two gases = the square root of the inverse of their molar masses:

$\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{M_2}{M_1} }$

M₁ = molar mass Ammonia NH₃= 17

M₂ = molar mass Silicon tetra bromide SiBr₄= 348

$\rm \dfrac{r_1}{r_2}=\sqrt{\dfrac{348}{17} }=4.5$

the rate of effusion of Ammonia = 4.5 faster than Silicon tetra bromide

3 0

3 years ago

What is the balanced form of the chemical equation shown below?<br> Cr(s) + Cl2(g) → CrCl3(s)

loris [4]

Answer:

${ \sf{2Cr _{(s)} + 3Cl _{2(g)} → 2CrCl _{3(g)} }}$

4 0

3 years ago

Read 2 more answers

Need some help anyoneee like bad bad

crimeas [40]

Answer:

D. CF₄

Explanation:

The compound with this molecular geometry is Carbon tetrafluoride (CF₄)

Carbon tetrafluoride (CF₄) also known as Tetrafluoromethane, is known to be the simplest perfluorocarbon. The compound, tetrafluoromethane is the hydrocarbon methane has been perfluorinated. It useful as a refrigerant but known to be a greenhouse gas. Due to the nature of the carbon-flourine bond, it has very high bonding strength. Its bonds are known to be the strongest single bonds in organic chemistry.

Option D is the correct answer.

3 0

3 years ago