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3 years ago

What is the mass number of an atom that contains 85 protons 133 neutrons and 85 electrons

Chemistry

1 answer:

Vikentia [17]3 years ago

6 0

The mass would be the sum of the protons and neutrons. Your answer would be 218

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Design a concept map that shows the relationships among the following terms: volume , derived unit , mass , base unit , time , a

Svetlanka [38]

Base unit is the fundamental unit of measurement that is not mutually dependent. The seven base units are,

Length - meter

Mass- kilogram

Time - second

Temperature - Kelvin

Current - Ampere

Luminous intensity - Candela

Amount of matter - mole

Derived units are derived from the seven base units. Like the area (square meters) is the square of length (meters), volume is the cube of length.

5 0

3 years ago

How much does 0.0273 moles of Na2O weigh

devlian [24]

Answer:

1.69 g Na₂O

General Formulas and Concepts:

Chemistry - Atomic Structure

Reading a Periodic Table
Using Dimensional Analysis

Explanation:

Step 1: Define

0.0273 mol Na₂O

Step 2: Identify Conversions

Molar Mass of Na - 22.99 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of Na₂O - 2(22.99) + 16.00 = 61.98 g/mol

Step 3: Convert

$0.0273 \ mol \ Na_2O(\frac{61.98 \ g \ Na_2O}{1 \ mol \ Na_2O} )$ = 1.69205 g Na₂O

Step 4: Check

We are given 3 sig figs. Follow sig fig rules and round.

1.69205 g Na₂O ≈ 1.69 g Na₂O

6 0

3 years ago

Gallium arsenide, GaAs, has gained widespread use in semiconductor devices that convert light and electrical signals in fiber-op

stira [4]

Answer:

Five peaks

Explanation:

GaAs would show two peaks:

Ga-69 + As-75 = 144

Ga-71 + As-75 = 146

Their intensities are in the ratio 60 : 40 = 100:67.

Ga₂S₂ would show three peaks:

Ga-69 + Ga-69 + 2As-75 = (Ga-69)₂(As-75)₂ = 288

Ga-69 + Ga-71 + 2As-75 = (Ga-69)(Ga-71(As-75)₂ = 290

Ga-71 + Ga-71 + 2As-75 = (Ga-71)₂(As-75)₂ = 292

Their relative intensities are in the ratio

(60 + 40)² = 60² : 2×60×40 : 40² = 3600 : 4800 : 1600 = 75 : 100 : 33

A spectrum of a mixture of GaAs and Ga₂As₂ would show five peaks:

Two at m/e 144 and 146 with intensity ratios 100: 67 and

Three at m/e 288, 290, and 292 with intensity ratios 75:100 :33.

We cannot predict the absolute sizes of the peaks because we do not know the relative amounts of GaAs and GaAs₂.

6 0

4 years ago

Calculate ΔHo for the following reaction ussing the given bond dissociation energiesCH4(g) + 2O2(g) --> CO2(g) + 2H2O(g)BOND

Mazyrski [523]

Answer:

The ΔH° for the following reaction is -794 kJ, hence exothermic reaction,

Explanation:

$CH_4(g) + 2O_2(g)\rightarrow CO_2(g) + 2H_2O(g) ,$ ΔH° = ?

We are given with:

$\Delta H_{O-O}=142 kJ/mol$

$\Delta H_{O=O}=498 kJ/mol$

$\Delta H_{H-O}=459 kJ/mol$

$\Delta H_{C-H}=411 kJ/mol$

$\Delta H_{C-O}=358 kJ/mol$

$\Delta H_{C=O}=799 kJ/mol$

ΔH° =

(Energies required to break bonds on reactant side) - (Energies released on formation of bonds on product side)

$\Delta H^o=(1 mol\times 4\times \Delta H_{C-H}+2 mol\times 1\times \Delta H_{O=O})-(1 mol\times 2\times \Delta H_{C=O}+2 mol\times 2\times\Delta H_{H-O})$

$\Delta H^o=(1 mol\times 4\times 411 kJ/mol+2 mol\times 1\times 498 kJ/mol)-(1 mol\times 2\times 799 kJ/mol+2 mol\times 2\times 459 kJ/mol)$

$\Delta H^o=-794kJ$

$\Delta H^o>0$ endothermic reaction

$\Delta H^o$ exothermic reaction

The ΔH° for the following reaction is -794 kJ, hence exothermic reaction,

4 0

4 years ago

Which data are shown on topographic maps?

eimsori [14]

Answer:

Topographic maps generally shows Natural features such as Rivers and Lakes.

sometimes they also show some features made by humans like brodges, elevations etc.

4 0

2 years ago

Read 2 more answers

What is the mass number of an atom that contains 85 protons 133 neutrons and 85 electrons​

What is the mass number of an atom that contains 85 protons 133 neutrons and 85 electrons