All categories

2 years ago

How many grams of KBr are required to make 550. mL of a 0.115 M KBr solution?

1 answer:

4 0

Molarity is expressed as the number of moles of solute per volume of the solution. For example, we are given a solution of 2M NaOH this describes a solution that has 2 moles of NaOH per 1 L volume of the solution. We calculate as follows:

0.115 M = n mol KBr / .55 L solution

n = 0.06325 mol KBr

mass = 0.06325 mol KBr (119 g / mol) = 7.53 g KBr

You might be interested in

Hypochlorous acid decays in the presence of ultraviolet radiation. Assume that degradation occurs accord- ing to first-order kin

Dennis_Churaev [7]

Answer:

35.75 days

Explanation:

From the given information:

For first-order kinetics, the rate law can be expressed as:

$\mathsf{In \dfrac{C}{C_o} = -kt}$

Given that:

the rate degradation constant = 0.12 / day

current concentration C = 0.05 mg/L

initial concentration C₀ = 3.65 mg/L

$\mathsf{In( \dfrac{0.05}{3.65})= -(0.12) t}$

㏑(0.01369863014) = -(0.12) t

-4.29 = -(0.12)

t = -4.29/-0.12

t = 35.75 days

3 0

2 years ago

Just as one dozen eggs always has 12 eggs in it, one mole of a

zzz [600]

Answer:

$6.022x10^{23}atoms \ Al$

Explanation:

Hello,

In this case, given the described concept regarding the Avogadro's number, we can easily notice that 27.0 g of aluminium foil has 6.022x10²³ atoms as shown below based on the mass-mole-particles relationship:

$27.0gAl*\frac{1molAl}{27.0gAl} *\frac{6.022x10^{23}atoms \ Al}{1molAl} \\\\=6.022x10^{23}atoms \ Al$

Notice this is backed up by the fact that aluminium molar mass if 27.0 g/mol.

Best regards.

8 0

2 years ago

Which three groups of the periodic table contain the most elements classified as metalloids (semimetals)?

attashe74 [19]

The metalloids are mostly concentrated in groups 14, 15, and 16. (Some simpler charts will show them as 4A, 5A, and 6A - take a look at the top of the periodic table your class uses to double-check).

If you like my answer, please vote me a 'brainliest' - trying to improve my rank :-)

8 0

2 years ago

Read 2 more answers

Which set of reagents will best convert 2,2-dimethylpropan-1-ol (neopentyl alcohol) to 4,4-dimethylpentan-2-ol

Sladkaya [172]

Answer:

SOCl2, Mg, CH3CHO, H3O^+

Explanation:

The reaction of the 2,2-dimethylpropan-1-ol with SOCl2 converts the alcohol to an alkyl halide. This now reacts with Mg metal to yield a Grignard reagent.

The Grignard reagent reacts with CH3CHO and acid to yield 4,4-dimethylpentan-2-ol as shown in the image attached to this answer.

6 0

2 years ago

In which environment would a forensic scientist not be found?

mrs_skeptik [129]

The correct answer is D. In a police interrogation room, questioning the suspect.

Explanation:

Forensic scientists are experts who use science as part of criminal investigations. Indeed, the main role of these experts is to deal with the evidence related to the crime to help authorities understand how the crime occurred and who was involved in this.

Because of this, the forensic scientist's role includes collecting evidence, analyzing samples, participating as witnesses in trials, and in some cases teach other experts about techniques. However, forensic scientists cannot interrogate suspects as they only deal with evidence and this process is in charge of the police.

6 0

2 years ago