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3 years ago

Which of the following is an example of an exothermic reaction?

Chemistry

2 answers:

Alja [10]3 years ago

7 0

Fire Burning is the correct answer

e-lub [12.9K]3 years ago

7 0

Answer:

ice melting

Explanation:

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Which element(s) are not balanced in this equation ?

Alekssandra [29.7K]

Only the Fe is unbalanced.
:)

3 0

3 years ago

Read 2 more answers

The density of lead is 11.4g/cm3. What volume, in ft3, would be occupied by 10.0 g of lead?

yawa3891 [41]

Answer:

3.10×10¯⁵ ft³.

Explanation:

The following data were obtained from the question:

Density (D) of lead = 11.4 g/cm³

Mass (m) of lead = 10 g

Volume (V) of lead =.?

Density (D) = mass (m) / Volume (V)

D = m/V

11.4 = 10 / V

Cross multiply

11.4 × V = 10

Divide both side by 11.4

V = 10 / 11.4

V = 0.877 cm³

Finally, we shall convert 0.877 cm³ to ft³. This can be obtained as follow:

1 cm³ = 3.531×10¯⁵ ft³

Therefore,

0.877 cm³ = 0.877 cm³ × 3.531×10¯⁵ ft³ /1 cm³

0.877 cm³ = 3.10×10¯⁵ ft³

Thus, 0.877 cm³ is equivalent to 3.10×10¯⁵ ft³.

Therefore, the volume of the lead in ft³ is 3.10×10¯⁵ ft³.

7 0

3 years ago

What do genotype will appear in boxes 2 and 3?

VMariaS [17]

Tt is the genotype that will appear in boxes two and three.

If you look at the column and row that intersect to form boxes two and three, you will see that they are T and t. That is the best way I can describe it, sorry if it’s confusing.

3 0

3 years ago

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In 1939, the use of DDT (a powerful synthetic chemical) as an insecticide was discovered. The United States adopted its widespre

Natasha_Volkova [10]

Main advantages of DDT are the insecticide property and the knoledge about its chemical synthesis.

Explanation:

At that time in 1939 it was discovered that DDT have insecticide properties. It is a useful property because it allows inhibition of insects populations in large areas. Killing insects will reduce the diseases transmitted by them as typhus and malaria. More over you prevent the destruction of the agricultural crops by the harmful insects.

However the synthesis of the molecule was known way back in 1874. From that time it was plenty of time in which chemistry knowledge evolved so the synthesis at kilograms scale was implemented. High quantities of DDT molecule become available for the market so that in 1945 was available as agricultural insecticide.

It was discovered that DDT have bad effects for human health and also over time some insects developed resistance and their were not affected anymore by the molecule.

You may find the chemical structure of DDT in the attached figure.

Lean more:

about DDT

brainly.com/question/1417051

#learnwithBrainly

8 0

3 years ago

Three mixtures were prepared from three very narrow molar mass distribution polystyrene samples with molar masses of 10,000, 30,

8_murik_8 [283]

Answer:

(a). 46,666.7 g/mol; 78,571.4 g/mol

(b). 86950g/mol; 46,666.7 g/mol.

(c). 86950g/mol; 43,333.33 g/mol

Explanation:

So, we are given the molar masses for the three samples as: 10,000, 30,000 and 100,000 g mol−1.

Thus, the equal number of molecule in each sample = ( 10,000 + 30,000 + 100,000 ) / 3 = 46,666.7 g/mol.

The average molar mass = [ ( 10,000)^2 + (30,000)^2 + 100,000)^2] ÷ 10,000 + 30,000 + 100,000 = 78,571. 4 g/mol.

(b). The equal masses of each sample = 3/[ ( 1/ 10,000) + (1/30,000 ) + (1/100,000) ] = 20930.23 g/mol.

Average molar mass = ( 10,000 + 30,000 + 100,000 ) / 3 = 46,666.7 g/mol.

(c). Equal masses of the two samples = (0.145 × 10,000) + (0.855 × 100,000)/ 0.145 + 0.855 = 86950g/mol.

The weight average molar mass = 1.7 + 10,000 + 100,000/ 1.7 + 1 = 43,333.33 g/mol.

6 0

3 years ago