Why must the surface of a mineral be different color than the interior of the mineral?

Choose the appropriate volumetric device to use for each of the volume measuring applications.

Oksanka [162]

Answer:

1. Beaker and Flask: These two volumetric devices are used to make coarse measurements of volume. These devices have graduated volume measurements marked on the side if the beaker and flask. The beaker and flask have a 5% accuracy.

2. Graduated Cylinder: More accurate than beakers and flask, with a 1% accuracy. Graduated cylinder are transparent with finely divided graduations. Their size vary from 5mL to 200mL.

3. Burets: These are cylindrical glassware with a valve at the bottom (commonly called a “stopcock”). They also have graduations on the side for accurate reading, and they have a 0.01mL accuracy.

4. Pipets: 12-24 inches long slender tubes, that measure predetermined volume. Mohr pipets are volumetric glassware pipets with graduations used to measure odd or fractional volumes to be provided. They have a 0.02mL accuracy. There are three types of pipets: air-displacements; positive-displacement; and the dispenser pipet.

Explanation:

4 0

3 years ago

If a temperature increase from 12. 0 °C to 20. 0 °C doubles the rate constant for a reaction. What is the value of the activatio

stellarik [79]

If a temperature increase from 12. 0 °C to 20. 0 °C doubles the rate constant for a reaction. What is the value of the activation barrier for the reaction is 60.155KJ/mol.

<h3>What is activation energy? </h3>

Activation energy is defined as the minimum amount of energy required by molecules to occur a chemical reaction. It is denoted by Ea.

Given,

T1 = 12+273 = 285K

T2 = 20 +273 = 293K

Rate constant = k2/k1 = 2:1

Using arrhenius equation which give relationship between constant of reaction and temperature is

In(k2/k1) = Ea/(R[1/T1 - 1/T2]

where, Ea is the activation energy

and R is the gas constant

T1 is the initial temperature

T2 is the final temperature

In2= Ea/R[(1/285) - (1/293)]

Ea = In2 × 8.314 ×285×293/8

Ea = 0.301 ×8.314 ×285×293/8

Ea = 60155J/mol

Ea = 60.155KJ/mol.

Thus we calculated that the activation energy for a reaction at 12°C to 20°C is 60.155KJ/mol.

learn more about activation energy:

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6 0

2 years ago

Which statements correctly compare the masses of protons neutrons and electrons

Liono4ka [1.6K]

Protons and neutrons have similar mass. Electrons are smaller than a proton or a neutron. An atomic scientist was studying an atom and through experimentation found that the total negative charge of the area surrounding the nucleus is -9.

7 0

3 years ago

What is the mass of 3.01 x 10^21 atoms of Co

OlgaM077 [116]

Answer:

0.295 g Co

General Formulas and Concepts:

Chemistry - Atomic Structure

Reading a Periodic Table
Using Dimensional Analysis
Avogadro's Number - 6.022 × 10²³ atoms, molecules, formula units, etc.

Explanation:

Step 1: Define

3.01 × 10²¹ atoms Co

Step 2: Identify Conversions

Avogadro's Number

Molar Mass of Co - 58.93 g/mol

Step 3: Convert

$3.01 \cdot 10^{21} \ atoms \ Co(\frac{1 \ mol \ Co}{6.022 \cdot 10^{23} \ atoms \ Co} )(\frac{58.93 \ g \ Co}{1 \ mol \ Co} )$ = 0.294552 g Co

Step 4: Check

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

0.294552 g Co ≈ 0.295 g Co

5 0

3 years ago

The molecular weight of table salt, NaCl, is 58.5 g/mol. A tablespoon of salt weighs 6.37 grams. Calculate the number of moles o

finlep [7]

Answer:

0.109 mol/tablespoon

Explanation:

6.37 g/ 58.5 mol = 0.10888888 mol (0.109 significantly)

3 0

3 years ago