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Alenkinab [10]
3 years ago
7

A chemist weighed out 20.7 g of sodium . Calculate the number of moles of sodium she weighed out

Chemistry
1 answer:
Pachacha [2.7K]3 years ago
8 0

Answer:

about 0.9 mol

Explanation:

there are 22.990 g/mol of Na

20.7/22.99 = 0.900391 mol

about 0.9 mol

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How many grams of H2 will be produced, given 27.4 g of Al to start with?
pishuonlain [190]
3.07g H2

27.4/26.98/2x3x1.01x2=3.07
6 0
3 years ago
The half-life of a pesticide determines its persistence in the environment. A common pesticide degrades in a first-order process
denis23 [38]

Answer:

0.1066 hours

Explanation:

A common pesticide degrades in a first-order process with a rate constant (k) of 6.5 1/hours. We can calculate its half-life (t1/2), that is, the times that it takes for its concentration to be halved, using the following expression.

t1/2 = ln2/k

t1/2 = ln2/6.5 h⁻¹

t1/2 = 0.1066 h

The half-life of the pesticide is 0.1066 hours.

7 0
3 years ago
How does nuclear reactor produce electricty
taurus [48]

With a process called Fission. This generates heat to produce steam.

7 0
3 years ago
The bonds in the reactants of Figure 7-3 contained 372 kJ of chemical energy and the bonds in the products contained 350 kJ of c
satela [25.4K]

Answer: 22 kJ amount of energy is released in the following reaction.

Explanation: There are two types of reaction on the basis of amount of heat absorbed or released.

1. Endothermic reactions: These are the type of reactions in which reactants absorb heat to form the products. The energy of the reactants is less than the energy of the products.

2. Exothermic reactions: These are the type of reactions in which heat is released from the chemical reactions. The energy of the products is less than the reactants.

Sign convention for \Delta H: This value is negative for exothermic reactions and positive for endothermic reactions.

For the given chemical reaction,

Energy of the products is less than the energy of the reactants, Hence, this reaction will be a type of exothermic reaction and energy will be released during this chemical change.

Amount of energy released = (350 - 372) kJ = -22kJ

Negative sign symbolizes the energy is being released. So, 22 kJ amount of energy is released in the following reaction.

6 0
3 years ago
Please help!! I don’t think I did this right.?
harkovskaia [24]

Answer:

It was done correctly, Your answer is completely correct.

Explanation:

8 0
3 years ago
Read 2 more answers
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