PLEASEEEE I NEED HELPP

. How many grams of NaOH would you need to make 450 mL of a 0.250 M NaOH solution

Stella [2.4K]

You have molarity and you have volume. Use the formula :
Molarity(M)= Moles(N)/Liter(L) to get the solution.
450 ml= .450 L
.250 = N/.450
N=.1125 moles of NaOH.
And since you know the moles, use the molar mass to figure out the grams.
 (40g/mol NaOH) x (.1125 mol) =
4.5g of NaOH.

Hope it helps. Good luck on chemistry.

7 0

3 years ago

What is the emperical formula of a compound containing 40.1% carbon and 6.6% hydrogen

levacccp [35]

Answer:

CH₂

Explanation:

Given parameters:

Percentage composition:

Carbon = 40.1%

Hydrogen = 6.6%

Unknown:

Empirical formula of the compound = ?

Solution:

The empirical formula of a substance is its simplest formula.

Elements Carbon Hydrogen

Percentage

Composition 40.1 6.6

Molecular mass 12 1

Number of moles 40.1/12 6.6/1

3.342 6.6

Divide through by

the smallest 3.342/3.342 6.6/3.342

1 2

So the empirical formula of the compound is CH₂

5 0

2 years ago

What is measured by the reaction rate? the probability that a reaction will occur the speed at which products form the time requ

Cloud [144]

Answer: the speed at which products form

Explanation:

Rate of a reaction is defined as the speed at which a chemical reaction proceeds. It is often expressed in terms of the concentration of a reactant that is consumed in a unit time or the concentration of a product that is formed in a unit of time.

For a general reaction : $A\rightarrow B$

$Rate=-\frac{d[A]}{dt}$

or $Rate=+\frac{d[B]}{dt}$

where d[A] = change in concentration of reactant A

d[B] = change in concentration of product B

dt = time interval

5 0

2 years ago

In the first step of glycolysis, the given two reactions are coupled. reaction 1: glucose + P i ⟶ glucose - 6 - phosphate + H 2

Alika [10]

Answer:

Check the explanation

Explanation:

Glycolysis is the process in the field of chemistry in which a specific glucose molecule is broken down to become two or more molecules of pyruvic acid or pyruvate. The process and procedure is a metabolic multi-step pathway that happens in the cytoplasm of plant cells, animal cells, and the cells of various microorganisms.

The answer to the question above is:

1) nonspontaneous because deltaG is positive

2) glucose + ATP --> glucose-6-phosphate + ADP

3) -16.7 kJ/mol

4) yes, because deltaG is negative

6 0

2 years ago

PLEASE ANSWER Which is/are true?

Alona [7]

You have to check each statement, so this is equivalent to 5 different questions.

Answers:

The true statements are:

b. Si has valence electrons in the n = 3 energy level.

d. Xe has valence electrons in the n = 5 energy level.

Explanations:

a. Li has valence electrons in the n = 1 energy level.

Answer: False.

Valence electrons are the electrons in the outermost main energy level (shell of electrons).

To determine where the valence electrons are, you build the electron configuration, using Aufbau rules to predict the orbital filling: in increasing order of energy.

The atomic number of lithium (Li) is 3. Hence, you have to distribute 3 electrons, and so its electron confiuration is:

1s² 2s¹

The only valence electron is in the 2s orbital, i.e. in the n = 2 energy level.

b. Si has valence electrons in the n = 3 energy level.

Answer: True

Silicon (Si) has atomic number 14, so you have to distribute 14 electrons in increasing order of energy:

1s² 2s² 2p⁶ 3s² 3p²

Thus, Si has five valence electrons, and they are in the n = 3 energy level.

c. Ga has valence electrons in the n = 3 energy level.

Answer: False

Gallium has atomic number 31, so you have to distribute 31 electrons, filling the orbitals in increasing order of enery.

1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p¹

The highest energy level is 4. This is where the valence electrons are. So, Ga has the valence electrons in the n = 4 level (not n = 3 as the statement describes).

d. Xe has valence electrons in the n = 5 energy level.

Answer: True

The atomic number of Xe is 54.

Using the short notation (noble gas notation), and filling the orbitals in increasing order of energy, you get the configuration:

[Kr] 5s² 4d¹⁰ 5p⁶.

Hence, the valence electrons are in the n ) 5 level, such as the statement describes.

e. P has valence electrons in the n = 2 energy level.

Answer: False

Phosphorus (P) has atomic number 15, hence there are 15 electrons.

The electron configuration following the increasing order of energy, which you can remember using Aufbau rules, is:

1s² 2s² 3s² 3p³

Then, the valence electrons are in the n = 3 energy level; not in the n = 2 energy level.

3 0

2 years ago