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3 years ago

A copper wire is made of copper (Cu) atoms. Which of the following best describes the copper atoms?

Chemistry

2 answers:

Maslowich3 years ago

4 0

Answer: They are all basically the same, but the number of neutrons could vary.

Explanation: The atoms of an element are basically alike. However, atoms of the same element can have different numbers of neutrons and electrons. The number of protons is always the same for atoms of the same element.

Evgesh-ka [11]3 years ago

3 0

Answer: Option (A) is the correct answer.

Explanation:

An element is defined as a substance that contains atoms of same type.

As copper wire is a substance that is made up of only atoms of copper. And, all these atoms of copper will be the same. Hence, it is an element.

This means that all the atoms of copper will have same number of protons, neutrons and electrons.

Thus, we can conclude that the statement they are all exactly the same best describes the copper atoms.

You might be interested in

What is the atomic number of pt-175 after it undergoes alpha decay

DanielleElmas [232]

Answer:

Explanation:

Alpha decay is one of the most basic forms of radioactive decay. It has an atomic mass of 4 and a proton number of two.

Undergoing an alpha decay will decrease the atomic mass by four and the atomic number by two.

In this particular question, we are particular about the atomic number. The atom has an atomic number of 78. So taking 2 off this gives 76

5 0

3 years ago

Type the correct answer in the box. Express your answer to three significant figures. Calcium nitrate reacts with sodium phospha

RoseWind [281]

6.07 grams is the theoretical yield of calcium phosphate (Ca₃(PO₄)₂).

<h3>How we calculate mass from moles?</h3>

Mass of any substance can be calculated by using moles as:

n = W/M, where

W = required mass

M= molar mass

Given chemical reaction is:

3Ca(NO₃)₂ + 2Na₃PO₄ → 6NaNO₃ + Ca₃(PO₄)₂

From the stoichiometry it is clear that:

3 moles of Ca(NO₃)₂ = produce 1 mole of Ca₃(PO₄)₂

Given mass of Ca(NO₃)₂ = 96.1g

Mole of Ca(NO₃)₂ = 96.1g/164g/mol = 0.5859moles

So, 0.5859 moles of Ca(NO₃)₂ = produce 0.5859×1/3 = 0.0196 moles of Ca₃(PO₄)₂

Required mass of Ca₃(PO₄)₂ will be calculated by using moles as:

W = 0.0196mole × 310g/mole = 6.07 grams

Hence, 6.07 grams is the theoretical yield of calcium phosphate.

To know more about moles, visit the below link:

brainly.com/question/15373263

7 0

2 years ago

The protein lysozyme unfolds at a transition temperature of 75.5°C, and the standard enthalpy of transition is 509 kJ mol-1. Cal

spin [16.1K]

Answer:

0.4774 KJ/K.mol

Explanation:

We are told that the transition at 25.0°C occurs in three steps. Steps i, ii and iii.

Thus;

the entropy of unfolding of lysozyme = ΔS_i + ΔS_ii + ΔS_iii

Now,

C_p,m(unfolded protein) = C_p,m(folded protein) + 6.28 kJ/K.mol

Now, for the first process, ΔS_i is given as;

ΔS_i = C_p,m × In(T2/T1)

We are given;

T1 = 25°C = 25 + 273.15K = 298.15 K

T2 = 75.5°C = 75.5 + 273.15 K=348.65 K

Thus;

ΔS_i = C_p,m × In(348.65/298.15)

Now, for the third process, ΔS_iii is given as;

ΔS_iii = (C_p,m + 6.28 kJ/K.mol) × In(T1/T2)

Thus;

ΔS_iii = (C_p,m + 6.28 kJ/K.mol) × In(298.15/348.65)

Now, we don't know C_pm. So, we have to find a way to eliminate it. We will do it by rewriting In(298.15/348.65) in such a way that when ΔS_iii is added to ΔS_i, C_p,m will cancel out. Thus;

In(298.15/348.65) can also be written as;

In(348.65/298.15)^(-1) or

- In(348.65/298.15)

Thus;

ΔS_iii = - [(C_p,m + 6.28 kJ/K.mol) × In(298.15/348.65)]

Now, let's add ΔS_iii to ΔS_i to get;

ΔS_i + ΔS_iii = [C_p,m × In(348.65/298.15)] + [(-C_p,m - 6.28 kJ/K.mol) × In(348.65/298.15)]

ΔS_i + ΔS_iii = [C_p,m × In(348.65/298.15)] - [C_p,m × In(348.65/298.15)] - [6.28In(348.65/298.15)]

First 2 terms will cancel out to give;

ΔS_i + ΔS_iii = -6.28In(348.65/298.15)

ΔS_i + ΔS_iii = -0.9826 KJ/K.mol

Now,for process ii;

ΔS_ii = standard enthalpy of transition/Transition Temperature

Thus;

ΔS_ii = (509 KJ/K.mol)/348.65

ΔS_ii = 1.46 KJ/K.mol

Thus;

the entropy of unfolding of lysozyme = ΔS_i + ΔS_ii + ΔS_iii = -0.9826 + 1.46 = 0.4774 KJ/K.mol

5 0

3 years ago

At a given temperature, 2.6 atm of h2 and 3.14 atm of cl2 are mixed and allowed to come to equilibrium. the equilibrium pressure

Keith_Richards [23]

The solution would be like this for this specific problem:

Given:

H2 = 2.6 atm
CL2 = 3.14 atm

pressure H2 = 2.6 - x
pressure Cl2 = 3.14 - x
pressure HBr = 2x = 1.13

x = 1.13 / 2 = 0.565

pressure H2 = 2.6 - 0.565 = 2.035
pressure Br2 = 3.14 - 0.565 = 2.575

Kp = (1.13)^2 / 2.035 x 2.575

= 1.2769 / (5.240125)

= 0.24367739319195629875241525726963

= 0.244

Therefore, the Kp for the reaction at the given temperature is 0.244.

To add, the hypothetical pressure of a gas if it alone occupied the whole volume of the original mixture at the same temperature is called the partial pressure or Kp.

7 0

3 years ago

When a 3.00 g 3.00 g sample of KBr KBr is dissolved in water in a calorimeter that has a total heat capacity of 1.36 kJ ⋅ K − 1

cupoosta [38]

Answer:

Molar heat of solution of KBr is 20.0kJ/mol

Explanation:

Molar heat of solution is defined as the energy released (negative) or absorbed (Positive) per mole of solute being dissolved in solvent.

The dissolution of KBr is:

KBr → K⁺ + Br⁻

In the calorimeter, the temperature decreases 0.370K, that means the solution absorbes energy in this process. The energy is:

q = 1.36kJK⁻¹ × 0.370K

q = 0.5032kJ

Moles of KBr in 3.00g are:

3.00g × (1mol / 119g) = 0.0252moles

Thus, molar heat of solution of KBr is:

0.5032kJ / 0.0252moles = 20.0kJ/mol

3 0

3 years ago