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jonny [76]
3 years ago
8

Can someone please help me with these three questions, it will soon be due.

Chemistry
1 answer:
Mice21 [21]3 years ago
8 0

YOU also better mark me BRAINLIEST if someone else answers!!!

1)

volume = 100 mL

density = 1.02 g / mL

mass = density x volume

  • = 1.02 x 100
  • = 102 g
  1. Cp = 4.03 J / oc g
  2. dT = 28.7 - 23.5 = 5.2 oC
  3. Q = m Cp dT
  4. Q = 102 x 4.03 x 5.2
  5. Q = 2138 J
  6. Q = 2.14 kJ

heat absorbed = 2.14 kJ

2)

  • We can calculate the moles of HC1 present in 50 ml 1m solution by using the formula, moles = volume of solution  in L*molarity
  • moles = 50/1000 = .05 , L*1 M = .05 Moles of HCL.
  • The same can be applied for calculation  of moles fo  Na OH of 50 ml, 1 M solution. (50 ml NaOH = .o5 L NaOH)
  • Then use the formula = volume of solution / 1000*moles.wt,
  • =1.825 gram.
  • moles=mass in grams /moles.wt= .05 moles of HCI
  • calculate moles of water from this reaction.
  • HC1+NaOH----->NACl+h20 (Balanced Equation)
  • .5+.5----> .5+.5
  • .05 moles of water
  • Delta H=q/n.
  • n=.05 to calculate the Delat H.

3) I don't understand it, sorry


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Explanation:

The hardness of water is classified as;

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                                        Magnesium Sulfate   MgSO₄

                                        Magnesium Chloride   MgCl₂

These salts does not precipitate out on heating water.

Temporary Hard Water:
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                                        Calcium Bicarbonate  Ca(HCO₃)₂

                                        Calcium Carbonate  CaCO₃

                                        Magnesium Bicarbonate   Mg(HCO₃)₂

                                        Magnesium Carbonate  MgCO₃

These salts does not precipitate out on heating water. i.e.

                Ca(HCO₃)₂    -------heat------>    CaCO₃  +  CO₂  +  H₂O

The CaCO₃ are formed in the form of scales.

Result:
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Can DDT only be synthesized one way?
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Regulation Due to Health and Environmental Effects

The U.S. Department of Agriculture, the federal agency with responsibility for regulating pesticides before the formation of the U.S. Environmental Protection Agency in 1970, began regulatory actions in the late 1950s and 1960s to prohibit many of DDT's uses because of mounting evidence of the pesticide's declining benefits and environmental and toxicological effects. The publication in 1962 of Rachel Carson's Silent Spring stimulated widespread public concern over the dangers of improper pesticide use and the need for better pesticide controls.

In 1972, EPA issued a cancellation order for DDT based on its adverse environmental effects, such as those to wildlife, as well as its potential human health risks. Since then, studies have continued, and a relationship between DDT exposure and reproductive effects in humans is suspected, based on studies in animals. In addition, some animals exposed to DDT in studies developed liver tumors. As a result, today, DDT is classified as a probable human carcinogen by U.S. and international authorities.

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will accumulate in fatty tissues, and

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Current Status

Since 1996, EPA has been participating in international negotiations to control the use of DDT and other persistent organic pollutants used around the world. Under the auspices of the United Nations Environment Programme, countries joined together and negotiated a treaty to enact global bans or restrictions on persistent organic pollutants (POPs), a group that includes DDT. This treaty is known as the Stockholm Convention on POPs. The Convention includes a limited exemption for the use of DDT to control mosquitoes that transmit the microbe that causes malaria - a disease that still kills millions of people worldwide.

In September 2006, the World Health Organization (WHO) declared its support for the indoor use of DDT in African countries where malaria remains a major health problem, citing that benefits of the pesticide outweigh the health and environmental risks. The WHO position is consistent with the Stockholm Convention on POPs, which bans DDT for all uses except for malaria control.

DDT is one of 12 pesticides recommended by the WHO for indoor residual spray programs. It is up to individual countries to decide whether or not to use DDT. EPA works with other agencies and countries to advise them on how DDT programs are developed and monitored, with the goal that DDT be used only within the context of programs referred to as Integrated Vector Management. EXIT IVM is a decison-making process for use of resources to yield the best possible results in vector control, and that it be kept out of agricultural sectors.

Explanation:

hope this helps

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How many grams of SO3 are produced when 20.0 g FeS2 reacts with 16.0 g O2 according to this balanced equation
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Answer:

Aristotle's idea was to classify living beings.

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