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Svetllana [295]
3 years ago
14

You notice something is growing in a 100ml pot of liquid soap. You take 1ml of this liquid soap and perform a serial dilution an

d plate to determine the number of bacteria per 1ml in the liquid soap. On the 1:100,000 dilution you plate out 1ml and get a count of 37 colonies. How many bacteria were present in 1ml of soap (cfu/1ml)?
Chemistry
1 answer:
andrew-mc [135]3 years ago
6 0

Answer:

3'700,000 cfu

Explanation:

One way to count the amount of bacteria in a medium is by doing a dilution of the sample and count how many colonies growth. Each colony is a cfu (Colony forming units).

In the problem, you count 37 colonies. The dilution was 1:100,000. That means the bacteria present in the soap is:

37 colonies × (100,000 / 1) = <em>3'700,000 cfu</em>

<em></em>

I hope it helps!

You might be interested in
Name the following ionic compounds, keeping in mind that a transition metal cation must include its charge. ____________________
Lilit [14]

Answer :

(a) The name for TiO_2 is titanium(IV) oxide.

(b) The name for BaCl_2 is barium chloride.

(c) The name for CuCl_3 is copper(III) chloride.

(d) The name for KI is potassium iodide.

(e) The name for SrCl_2 is strontium chloride.

(f) The name for CuBr_2 is copper(II) bromide.

Explanation :

Ionic compound : It is defined as the compound which is formed when electron gets transferred from one atom to another atom.

Ionic compound are usually formed when a metal reacts with a non-metal.

The nomenclature of ionic compounds is given by:

1. Positive ion is written first.

2. The negative ion is written next and a suffix is added at the end of the negative ion. The suffix written is '-ide'.

3. In case of transition metals, the oxidation state are written in roman numerals in bracket in-front of positive ions.

(a) TiO_2

TiO_2 is an ionic compound because titanium element is a metal and oxygen element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.

The charge on tin is (+4) and the the charge on oxygen is (-2). Thus, the name for TiO_2 is titanium(IV) oxide.

(b) BaCl_2

BaCl_2 is an ionic compound because barium element is a metal and chlorine element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.

The charge on barium is (+2) and the the charge on chlorine is (-1). Thus, the name for BaCl_2 is barium chloride.

(c) CuCl_3

CuCl_3 is an ionic compound because copper element is a metal and chlorine element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.

The charge on copper is (+3) and the the charge on chlorine is (-1). Thus, the name for CuCl_3 is copper(III) chloride.

(d) KI

KI is an ionic compound because potassium element is a metal and iodine element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.

The charge on potassium is (+1) and the the charge on iodine is (-1). Thus, the name for KI is potassium iodide.

(e) SrCl_2

SrCl_2 is an ionic compound because strontium element is a metal and chlorine element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.

The charge on strontium is (+2) and the the charge on chlorine is (-1). Thus, the name for SrCl_2 is strontium chloride.

(f) CuBr_2

CuBr_2 is an ionic compound because copper element is a metal and bromine element is a non-metal. The bond formed between a metal and a non-metal is always ionic in nature.

The charge on copper is (+2) and the the charge on bromine is (-1). Thus, the name for CuBr_2 is copper(II) bromide.

3 0
3 years ago
Dr. I. M. A. Brightguy adds 0.1727 g of an unknown gas to a 125-mL flask. If Dr. B finds the pressure to be 736 torr at 20.0°C,
AlladinOne [14]

Answer:

The gas that Dr. Brightguy added was O₂

Explanation:

Ideal Gases Law to solve this:

P . V = n . R . T

Firstly, let's convert 736 Torr in atm

736 Torr is atmospheric pressure = 1 atm

20°C = 273 + 20 = 293 T°K

125 mL = 0.125L

0.125 L . 1 atm = n . 0.082 L.atm / mol.K . 293K

(0.125L .1atm) / (0.082 mol.K /L.atm . 293K) = n

5.20x10⁻³ mol = n

mass / mol = molar mass

0.1727 g / 5.20x10⁻³ mol = 33.2 g/m

This molar mass corresponds nearly to O₂

7 0
3 years ago
The chemical equation may not be balanced with HCI + NaOH
Masja [62]

Answer:

idk

Explanation:

3 0
3 years ago
Which of the following pairs are isotpes?
grin007 [14]
The answer is B because isotopes have the same number of protons and neutrons.
5 0
3 years ago
(d) carbon monoxide
Irina18 [472]

Answer:

D. carbon monoxide

Hope this helps :)

6 0
3 years ago
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