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3 years ago

Name 2 separate problems that occur when a sample for infrared analysis is contaminated with water.

Chemistry

1 answer:

Andreyy893 years ago

7 0

Explanation:

The water molecules gets trapped in the crystal structure to be analysed and will give a peak in the spectra at about 3500 /cm , and there by hindering with the IR spectra of the sample to be analysed .
The second problem with the contamination of the sample with water is , that water makes the potassium bromide disc opaque which will decrease the absorption of the IR by the sample .

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If the same amount of heat is added to 25.0 g of each of the metals, which are all at the same initial temperature, which metal

AVprozaik [17]

Answer:

The bismuth sample.

Explanation:

The specific heat $c$ of a substance (might not be a metal) is the amount of heat required for heating a unit mass of this substance by unit temperature (e.g., $\rm 1\; ^{\circ}C$ .) The formula for specific heat is:

$\displaystyle c = \frac{Q}{m \cdot \Delta T}$ ,

where

$Q$ is the amount of heat supplied.
$m$ is the mass of the sample.
$\Delta T$ is the increase in temperature.

In this question, the value of $Q$ (amount of heat supplied to the metal) and $m$ (mass of the metal sample) are the same for all four metals. To find $\Delta T$ (change in temperature,) rearrange the equation:

$\displaystyle c \cdot \Delta T = \frac{Q}{m}$ ,

$\displaystyle \Delta T = \frac{Q}{c \cdot m}$ .

In other words, the change in temperature of the sample, $\Delta T$ can be expressed as a fraction. Additionally, the specific heat of sample, $c$ , is in the denominator of that fraction. Hence, the value of the fraction would be the largest for sample with the smallest specific heat.

Make sure that all the specific heat values are in the same unit. Find the one with the smallest specific heat: bismuth ( $\rm 0.123 \; J \cdot g\cdot \,^{\circ}C^{-1}$ .) That sample would have the greatest increase in temperature. Since all six samples started at the same temperature, the bismuth sample would also have the highest final temperature.

3 0

2 years ago

12. Describe the results of a chemical change. List four<br> indicators of chemical change.

marshall27 [118]

Answer:

1. Color Change

2. Change in temperature

3. Noticiable Odor

4. Formation of bubbles

8 0

2 years ago

Number of molecules in 4HCl

katrin2010 [14]

Answer:

its not cear to answer this question

6 0

2 years ago

Explain what a glycosolation reaction is

AVprozaik [17]

Answer:

The glycosylation reaction or glycoside formation is an organic reaction in which the hemiacetal group of cyclists ketoses or aldoses turns into acetals, named glycosides. Reaction in the attached picture.

Explanation:

Carbohydrates can be found in an open-chain form or a cyclic form. For the second one, the carbonyl group of the aldehyde could react with the alcohol group of the molecule to form the cycle. As shown in the attached picture, the alcohol group of this cyclic form could react with an alcohol (like methanol) in acidic conditions to form an acetal. These compounds are stable at neutral and acidic conditions, but they hydrolyze at basic conditions. This reaction produces both acetals anomers (α and β) because the attack of the nucleophile (alcohol) could be from both sides. However, the most stable anomer will predominate.

3 0

3 years ago

First, get about 20 mL of the quinine stock solution in a clean beaker to prepare 250 mL of about 2 ppm quinine in 0.05 M H2SO4.

iris [78.8K]

Answer:

Volume of acid, Va=250mL; Volume of quinine,Vb=20mL; Molarity of acid, Ma=0.05M.

Molar mass of acid= H2+S+O4= 2+32+(16X4)= 2+32+64=98g

Concentration of acid, Ca= Molar mass of acid/ Ma =98/0.05=1960g/mol

Explanation: To calculate concentration of quinine, Cb is as follow

Va*Ca=Vb*Cb

∴ Cb=Va*Ca/Vb =250*1960/20 =24500g/mol

5 0

3 years ago