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3 years ago

How does the mass number of an element differ from its average atomic mass?

1 answer:

4 0

The mass number is the total number of protons and neutrons in a nucleus of an element. The average atomic mass is the sum of the masses of an element's isotopes, each multiplied by their abundance.

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Typical frequencies for several types of electromagnetic radiation are given below. Calculate the energy of each type of radiati

marusya05 [52]

Explanation:

The energy of electromagnetic radiation is given by :

$E=h\nu$

Where, h is the Planck's constant

(a) A gamma ray, $\nu = 1.64\times 10^{20}\ Hz$

Energy,

$E=6.63\times 10^{-34}\times 1.64\times 10^{20}\\E=1.08\times 10^{-13}\ J$

(b) A microwave, $\nu = 4.95\times 10^{10}\ Hz$

Energy,

$E=6.63\times 10^{-34}\times 4.95\times 10^{10}\\E=3.28\times 10^{-23}\ J$

Energy,

$E=6.63\times 10^{-34}\times 2\times 10^{6}\\E=1.32\times 10^{-27}\ J$

Therefore, this is the required solution.

4 0

2 years ago

Taylor, a MIC 206 student needs to determine the OCD of a sample of Escherichia coli. She performed dilutions using four 9 ml di

Troyanec [42]

Answer:

1.37 x $10^6$ CFU/mL

Explanation:

First, the dilution factor needs to be calculated.

Since four 9 ml dilution blanks were prepared, the dilution factor that yielded 137 colonies is of $10^{-4}$ .

Next is to divide the colony forming unit from the dilution by the dilution factor:

137/ $10^{-4}$ = 137 x $10^4$

In order to get the CFU/ml, divide the CFU from the dilution by the plated volume (1 mL) from the final dilution tube.

137 x $10^4$ /1 = 1.37 x $10^6$

Hence, the CFU/ml present in the original E. coli  sample is 1.37 x $10^6$ .

cfu/ml = (no. of colonies x dilution factor) / volume of culture plate

7 0

3 years ago

6th grade science i mark as brainliest

kiruha [24]

Answer:

it would be 5 i think

Explanation:

cuz 50 divided by 10 !

7 0

2 years ago

Read 2 more answers

what might cause the goldfish population to drop if the temperature moves out of its normal range? Name three things

Slav-nsk [51]

Answer:

Appearing disoriented, such as swimming upside down.

Leaving food uneaten.

White spots on fins or body.

Discolored gills.

Explanation:

Gold Fish are unable to regulate their body temperature, so they are influenced by the temperature around them. If the water is warm, gold fish metabolism accelerates, feeding and respiration increases, and there is a general increase in movement. If the water is cooler, fish become lethargic and tend to be inactive.

8 0

3 years ago

How many moles are in 125g of water?

ki77a [65]

To calculate number of moles, all you do is divide the given mass by the molecular molar mass:

i.e. 125g / 18g = 6.94444g 

Therefore, your answer is (a) 6.94 g

7 0

2 years ago