1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
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
Substances have more kinetic energy in the _______ state than in the _______ state. A. Gas; solid B. Solid; gas C. Solid; liquid
Elodia [21]
Substances have more kinetic energy in the gas state than in the solid state
6 0
3 years ago
The Environmental Protection Agency (EPA) and the National Highway Traffic Safety Administration (NHTSA) are coordinating standa
Ksivusya [100]

Answer:

Diminish reliance on foreign sources of oil

Explanation:

7 0
3 years ago
Read 2 more answers
Read the given expression. X = number of protons − number of core electrons Which of the following explains the identity of X an
shepuryov [24]

<u>Answer: </u>The correct statement is X is the effective nuclear charge, and it increases across a period.

<u>Explanation:</u>

We are given that:

X = number of protons − number of core electrons

Effective nuclear charge is defined as the actual nuclear charge (Z = number of protons) minus the screening effect caused by the electrons present between nucleus and valence electrons. These electrons are the core electrons.

The formula used for the calculation of effective nuclear charge given by Slater is:

Z^*=Z-\sigma

where,

Z^* = effective nuclear charge

Z = atomic number or actual nuclear charge or number of protons

\sigma = Screening constant

The effective nuclear charge increases as we go from left to right in a period because nuclear charge increases with no effective increase in screening constant.

Hence, the correct answer is X is the effective nuclear charge, and it increases across a period.

5 0
4 years ago
Based on the equation, how many grams of Br2 are required to react completely with 36.2 grams of AlCl3?
s2008m [1.1K]

Answer:

65.08 g.

Explanation:

  • For the reaction, the balanced equation is:

<em>2AlCl₃ + 3Br₂ → 2AlBr₃ + 3Cl₂,</em>

2.0 mole of AlCl₃ reacts with 3.0 mole of Br₂ to produce 2.0 mole of AlBr₃ and 3.0 mole of Cl₂.

  • Firstly, we need to calculate the no. of moles of 36.2 grams of AlCl₃:

<em>n = mass/molar mass</em> = (36.2 g)/(133.34 g/mol) = <em>0.2715 mol.</em>

<u><em>Using cross multiplication:</em></u>

2.0 mole of AlCl₃ reacts with → 3.0 mole of Br₂, from the stichiometry.

0.2715 mol of AlCl₃ reacts with → ??? mole of Br₂.

∴ The no. of moles of Br₂ reacts completely with 0.2715 mol (36.2 g) of AlCl₃  = (0.2715 mol)(3.0 mole)/(2.0 mole) = 0.4072 mol.

<em>∴ The mass of Br₂ reacts completely with 0.2715 mol (36.2 g) of AlCl₃ = no. of moles of Br₂ x molar mass</em> = (0.4072 mol)(159.808 g/mol ) = <em>65.08 g.</em>

4 0
3 years ago
If you burn 29.4 g of hydrogen and produce 263 g of water, how much oxygen reacted?
vovikov84 [41]

The reaction between hydrogen and oxygen to form water is given as:

H_2 + O_2 \rightarrow H_2O

The balanced reaction is:

2H_2 + O_2 \rightarrow 2H_2O

According to the balanced reaction,

4 g of hydrogen (4\times 1) reacts with 32 g of oxygen (2\times 16).

So, oxygen reacted with 29.4 g of hydrogen is:

\frac{29.4\times 32}{4} = 235.2 g

Hence, the mass of oxygen that is reacted with 29.4 g of hydrogen is 235.2 g.

7 0
3 years ago
Other questions:
  • 4 examples of Substances that sublime?
    14·1 answer
  • Complete the chemical change. _______ + e - → Cl-
    10·2 answers
  • Which of the following is the correct definition of radiant energy?
    15·2 answers
  • How many valence electrons are in an atom of phosphorus
    12·2 answers
  • What evidence reaction will be observed based on this chemical reaction​
    6·1 answer
  • the compound nacI is an example of a /an.. (A)covalent bond (B)Ionic bond (C) Metallic bond (D) none of the above
    8·1 answer
  • Given the reaction agi(s) ↔ ag+(aq) + i-(aq) solution equilibrium is reached in the system when
    5·1 answer
  • Express 2/10 in scientific notation
    5·1 answer
  • Why do ice cubes formed from water of a glacier freeze at a higher temperature than ice cubes formed from water of an undergroun
    15·2 answers
  • 2. Calculate: For each object, substitute the values you know into the gravitational potential energy equation to solve for weig
    12·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!