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konstantin123 [22]
3 years ago
9

How many protons are in the nucleus of this atom? What is the mass number of this atom?

Chemistry
1 answer:
Anettt [7]3 years ago
3 0
Ummmmmmmmmmmmmmmmmmmmmmmmm, 21

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New Moon, First Quarter, Full Moon, Last Quarter, Waxing Crescent, Waxing Gibbous, Waning Gibbous, and Waning Crescent.

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add x to 7 and divide by 3

Explanation:

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What is the modren system of classificationis based on
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8 0
3 years ago
Does anybody know how to do q4. Please show working out thanks.
insens350 [35]

Answer:

% purity of limestone = 96.53%

Explanation:

Question (4).

Weight of impure CaCO₃ = 25.9 g

Molecular weight of CaCO₃ = 40 + 12 + 3(16)

                                              = 100 g per mole

We know at S.T.P. number of moles of CO₂ = 1 and volume = 22.4 liters

From the given reaction, 1 mole of CaCO₃ reacts with 1 mole or 22.4 liters of

CO₂.

∵ 22.4 liters of CO₂ was produced from CaCO3 = 100 g

∴ 1 liter of CO₂ will be produced by CaCO₃ = \frac{100}{22.4}

∴ 5.6 liters of CO₂ will be produced by CaCO₃ = \frac{100\times 5.6}{22.4}

                                                                              = 25 g

Therefore, % purity of CaCO₃ = \frac{\text{Weight calculated}}{{\text{Weight given}}}\times 100

                                                 = \frac{25}{25.9}\times 100

                                                 = 96.53 %

7 0
3 years ago
Suppose you have 15.0 ml of zinc. What volume of aluminum would have the same mass as the zinc?
Black_prince [1.1K]

Answer:

\large \boxed{\text{41.2 cm}^{3}}

Explanation:

1. Mass of zinc

The density of zinc is 7.14 g/cm³

D = m/V

\begin{array}{rcl}7.14 & = & \dfrac{m}{15.0}\\\\m & = & 7.14 \times 15.0\\& = & \text{107.1 g}\\\end{array}\\

2. Volume of aluminium

The density of aluminium is 2.60/cm³.

\begin{array}{rcl}2.60 & = & \dfrac{107.1}{V}\\\\2.60V & = & 107.1\\V& = &\dfrac{107.1}{2.60}\\\\& = &\textbf{41.2cm}^{\mathbf{3}}\\\end{array}\\\large \boxed{\textbf{41.2 cm}^{\mathbf{3}}}\text{ of aluminium have the same mass as 15.0 cm$^{3}$ of zinc.}

5 0
3 years ago
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