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3 years ago

How many moles of NaCI are present in 0.75L of a 0.55M solution?

Chemistry

1 answer:

kolezko [41]3 years ago

6 0

Answer:

,4125 (or .41 if you go by sig figs)

Explanation:

M = (mol)/(L) is a formula for concentration, but we need to solve for moles, so rewrite it as

mol = (L)(M), where we can simply plug in values as follows:

# of mols = (.75L)(.55M) = .4125mol NaCl

The question has 2 significant figures, so you could also put .41 mol NaCl

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Give two reasons why scientists create models to study atoms.

mariarad [96]

IT will be easy to know how chemical reactions occur
It will helps to know the fundamental particles of an atom

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3 years ago

The specific spatial arrangement of amino acid residues that are close to each other in the polypeptide chain is called______the

natulia [17]

Answer:

c. tertiary.

Explanation:

In this case, we can review the definition of each level of structuration in the proteins:

Primary structure

In the primary structure, the amino acids are linked by peptide bonds. That is, the order of the amino acids is the criterion that defines this type of structure.

Secondary structure

In the secondary structure, we have to look at the way in which the protein is folded. The options are:

-) Beta-laminar: A structure in which the protein has a planar shape.

-) Alpha-helix: A structure in which the protein has a cross-strand form.

Tertiary structure

In the tertiary structure, the R groups that the amino acids have in the primary structure can generate interactions with each other. Interactions such as hydrogen bridges, dipole-dipole, hydrophobic interactions. This makes the protein have a very specific three-dimensional structure, on which its function depends.

Quaternary structure

In the quaternary structure, several subunits may be attached, or there may be prostatic groups (metals that can help to attach various protein units).

With all these in mind, the deffinition that fits with the description in the question is the tertiary structure.

I hope it helps!

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2 years ago

A student obtains a mixture of the chlorides of two unknown metals, X and Z. The percent by mass of X and the percent by mass of

Aleksandr-060686 [28]

Answer: The additional information that is helpful in calculating the mole percent of XCl(s) and ZCl(s) is the molar masses of Z and X

Explanation:

To calculate the mole percent of a substance, we use the equation:

$\text{Mole percent of a substance}=\frac{\text{Moles of a substance}}{\text{Total moles}}\times 100$

Mass percent means that the mass of a substance is present in 100 grams of mixture

To calculate the number of moles, we use the equation:

$\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}$

We require the molar masses of Z and X to calculate the mole percent of Z and X respectively

Hence, the additional information that is helpful in calculating the mole percent of XCl(s) and ZCl(s) is the molar masses of Z and X

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3 years ago

What is the iupac name of the following compound? 2,2-dimethyl-4-ethylheptane

Lady bird [3.3K]

Answer:

The IUPAC name of the compound has already been given which is 2,2-dimethyl-4-ethylheptane.

Explanation:

The IUPAC (International Union of Pure and Applied Chemistry) is an authority in chemistry that provides a guideline and standardized methods in the naming of compounds formed from the periodic table.

In order the give an IUPAC name to a compound, certain steps needs to be followed, these includes:

--> Identify the functional group in the compound as this will form the suffix. For example if the functional group is an alkane the suffix will be -ane.

--> Identify the longest carbon chain (it may not be a straight chain) that contains the functional group. This forms the prefix. Example: if the longest carbon chain is 7 carbon atoms then the prefix will be hept-

--> All the carbons of the longest chain should be numbered

--> Identify branched groups on the chain and name them according to the number of carbon atoms. They usually end with -yl.

--> Finally, combine the elements of the name is a single word.

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3 years ago

What would limit the population growth of rabbits in a forest ecosystem?

mihalych1998 [28]

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3 years ago