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densk [106]
3 years ago
13

Which is an example of gene modification that humans have done for thousands of years?

Chemistry
1 answer:
miv72 [106K]3 years ago
4 0
Cross breeding plants to make better apples
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How many atoms of carbon are in a container that has 0.450 mol of CO2 and 2.55 mol of CaC2?
Fantom [35]

Answer:

The number of carbon atoms in the container is 1.806 × 10²⁴ or the container contains 1.806 × 10²⁴ atoms of carbon

Explanation:

By Avogadro's number, 1 mole of a substance contains 6.02 × 10²³ particles of the substance

Here we have 0.45 mole of CO₂ contains

0.45 × 6.02 × 10²³ particles of CO₂ that is 2.709 × 10²³ particles of CO₂ or equivalent to 2.709 × 10²³ atoms of Carbon

Similarly, 2.55 moles of CaC₂ contains 2.55 × 6.02 × 10²³ particles of CaC₂ or 1.5351 × 10²⁴ atoms of Carbon

The total number of carbon atoms is therefore;

2.709 × 10²³ + 1.5351 × 10²⁴ = 1.806 × 10²⁴ atoms of carbon.

5 0
3 years ago
Which rule for assigning oxidation numbers IS correct?
Vilka [71]

Answer:

B.) Oxygen is usually -2

Explanation:

Hydrogen is usually +1.

A pure group 1 element is not always +1.

A monoatomic ion can be a range of numbers. However, it must be a charge other than 0.

3 0
1 year ago
Oxygen gas generated in an experiment is collected at 25.0°C in a bottle inverted in a trough of water. The total pressure is 1.
Nitella [24]

Answer:

0.007 mol

Explanation:

We can solve this problem using the ideal gas law:

PV = nRT

where P is the total pressure, V is the volume, R the gas constant, T is the temperature and n is the number of moles we are seeking.

Keep in mind that when  we collect a gas over water we have to correct for the vapor pressure of water at  the temperature in the experiment.

Ptotal = PH₂O + PO₂  ⇒ PO₂ = Ptotal - PH₂O

Since R constant has unit of Latm/Kmol we have to convert to the proper unit the volume and temperature.

P H₂O = 23.8 mmHg x 1 atm/760 mmHg =  0.031 atm

V = 1750 mL x 1 L/ 1000 mL = 0.175 L

T = (25 + 273) K = 298 K

PO₂ = 1 atm - 0.031 atm = 0.969 atm

n =  PV/RT = 0.969 atm x  0.1750 L / (0.08205 Latm/Kmol x 298 K)

n = 0.007 mol

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3 years ago
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ira [324]
Delete the cactus and the tree on the right for the first one and the third picture delete the lion moose Buffalo
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3 years ago
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Life as we know it could not exist without water. All the chemical reactions of life occur in an aqueous solution. Water molecul
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A) At 0 C water forms ice but as mentioned above F) water's greatest density occurs at 4 C and it decreases below 4 C so ice is lighter than 4C water, thus, at 0C ice comes to surface and acts as insulator thereby preventing lower water from freezing.
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