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Scilla [17]
3 years ago
7

How does skin defend the body against pathogens

Chemistry
2 answers:
bulgar [2K]3 years ago
6 0
Skin, tears and mucus are part of the first line of defence in fighting infection. They help to protect us against invading pathogens. You have beneficial bacteria growing on your skin, in your bowel and other places in the body (such as the mouth and the gut) that stop other harmful bacteria from taking over.
Morgarella [4.7K]3 years ago
4 0

Answer:

C. It blocks pathogens from getting inside the body.

Explanation:

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What is the name of a compound having the formula Al2O3? (5 points)
Andrew [12]

Answer:

4) Aluminum Oxide

Explanation:

4 0
3 years ago
Read 2 more answers
The carbon-14 content of a wooden harpoon handle found in an Inuit archaeological site was found to be 61.9% of the carbon-14 co
astraxan [27]

Answer:

3,964 years.

Explanation:

  • It is known that the decay of a radioactive isotope isotope obeys first order kinetics.
  • Half-life time is the time needed for the reactants to be in its half concentration.
  • If reactant has initial concentration [A₀], after half-life time its concentration will be ([A₀]/2).
  • Also, it is clear that in first order decay the half-life time is independent of the initial concentration.

  • The half-life of the element is 5,730 years.

  • For, first order reactions:

<em>k = ln(2)/(t1/2) = 0.693/(t1/2).</em>

Where, k is the rate constant of the reaction.

t1/2 is the half-life of the reaction.

∴ k =0.693/(t1/2) = 0.693/(5,730 years) = 1.21 x 10⁻⁴ year⁻¹.

  • Also, we have the integral law of first order reaction:

<em>kt = ln([A₀]/[A]),</em>

where, k is the rate constant of the reaction (k = 1.21 x 10⁻⁴ year⁻¹).

t is the time of the reaction (t = ??? year).

[A₀] is the initial concentration of the sample ([A₀] = 100%).

[A] is the remaining concentration of the sample ([A] = 61.9%).

∴ t = (1/k) ln([A₀]/[A]) = (1/1.21 x 10⁻⁴ year⁻¹) ln(100%/61.9%) = 3,964 years.

7 0
4 years ago
What is the mass of 0.50 mole of copper?<br> 63.5 grams<br> O 32 grams<br> 3.2 grams<br> 2.18 grams
Amanda [17]

Answer:

32 g Cu

Explanation:

1 mol Cu    -> 63.5 g

0.5 mol Cu ->x

x=(0.5 mol *63.5 g)/1 mol      x= 32 g Cu

3 0
3 years ago
This is in since class
Julli [10]

1 - causes the molecules of the object or surface it strikes to vibrate faster, increasing its temperature.

2-carbon dioxide, methane, nitrous oxide, and water vapor it has to be one of these 3

3-The greenhouse effect is the way in which heat is trapped close to Earth's surface by “greenhouse gases.”

4- because of the fossil fuels that people are burning for energy.

5- due to human activities

7 0
3 years ago
C12H22011+1202--&gt;12CO2+11H20
kogti [31]

Answer:

0.185moles

Explanation:

Given parameters:

Volume of O₂  = 49.8L

Unknown:

Number of moles of sucrose required  = ?

Solution:

We can assume that the reaction takes place at standard temperature and pressure.

From this, we can find the number of moles of oxygen that reacted and extrapolate to that of sucrose.

Chemical equation;

           C₁₂H₂₂0₁₁  +  120₂   →   12CO₂   +   11H₂0

Number moles  = \frac{volume of gas}{22.4}   at STP

Number of moles of oxygen gas = \frac{49.8}{22.4}   = 2.22moles

           12 moles of oxygen gas combines with  1 mole of sucrose

       2.22 moles of oxygen gas will combine with \frac{2.22}{12}   = 0.185moles

4 0
4 years ago
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