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defon
3 years ago
13

.Which of the following is true about elements?

Chemistry
2 answers:
Ludmilka [50]3 years ago
6 0

Answer:

C

Explanation:

Nesterboy [21]3 years ago
6 0
C. is the correct answer
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hello fellow men the challenge has officially begun do not answer this for one month (until november endes). okay well i wish yo
scZoUnD [109]

Answer:

I am not a man or boy, I am a girl so therefore I could answer this question before November ends Imao, have a great rest of your day.

Explanation:

5 0
3 years ago
Read 2 more answers
One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titrating a sample of silv
babunello [35]

Answer:

5.0x10⁻⁵ M

Explanation:

It seems the question is incomplete, however this is the data that has been found in a web search:

" One way the U.S. Environmental Protection Agency (EPA) tests for chloride contaminants in water is by titrating a sample of silver nitrate solution. Any chloride anions in solution will combine with the silver cations to produce bright white silver chloride precipitate. Suppose a EPA chemist tests a 250 mL sample of groundwater known to be contaminated with nickel(II) chloride, which would react with silver nitrate solution like this:

NiCl₂ + 2AgNO₃ →  2AgCl + Ni(NO₃)₂

The chemist adds 50 mM silver nitrate solution to the sample until silver chloride stops forming. She then washes, dries, and weighs the precipitate. She finds she has collected 3.6 mg of silver chloride. Calculate the concentration of nickel(II) chloride contaminant in the original groundwater sample. Round your answer to 2 significant digits. "

Keep in mind that while the process is the same, if the values in your question are different, then your answer will be different as well.

First we <u>calculate the moles of nickel chloride found in the 250 mL sample</u>:

  • 3.6 mg AgCl ÷ 143.32 mg/mmol * \frac{1mmolNiCl_{2}}{2mmolAgCl} = 0.0126 mmol NiCl₂

Now we <u>divide the moles by the volume to calculate the molarity</u>:

  • 0.0126 mmol / 250 mL = 5.0x10⁻⁵M
4 0
3 years ago
How many grams of water are made from the reaction of 16.0 grams of o2? given the reaction: 2h2 o2 --&gt; 2h2o
Jlenok [28]

Answer:

18.0 g H₂O

Explanation:

To find the mass of water (H₂O), you need to (1) convert grams O₂ to moles O₂ (via the molar mass), then (2) convert moles O₂ to moles H₂O (via mole-to-mole ratio from equation coefficients), and then (3) convert moles H₂O to grams H₂O (via the molar mass). It is important to arrange the conversions in a way that allows for the cancellation of units. The final answer should have 3 sig figs to match the sig figs of the given value.

Molar Mass (O₂): 2(15.998 g/mol)

Molar Mass (O₂): 31.996 g/mol

Molar Mass (H₂O): 2(1.008 g/mol) + 15.998 g/mol

Molar Mass (H₂O): 18.014 g/mol

2 H₂ + 1 O₂ -----> 2 H₂O

16.0 g O₂          1 mole            2 moles H₂O         18.014 g
---------------  x  ----------------  x  ---------------------  x  -----------------  = 18.0 g H₂O
                        31.996 g             1 mole O₂             1 mole

6 0
2 years ago
When an alkaline earth metal, a, reacts with a halogen, x, the formula of the covalent compund formed should be a2x?
Ierofanga [76]

Alkaline earth metal are the elements present in II group in the periodic table and are known as 'Metals' and have a charge of +2.

Alkaline earth metals - Be , Mg Ca, Sr , Ba, Ra

Halogens are present in VII A group in the periodic table and are 'Non-metals' and have a charge of -1.

Halogens - F, Cl, Br, I, At

When Alkaline earth metal (metals) combine with Halogens (non-metals) the compound formed will be ionic compound and the formula of the compound will be based on the charges of the element.

When we write the formula of the ionic compound the charges of the elements get criss crossed.

For example - Mg (Alkaline earth metal) have a charge of +2 and Cl (Halogen) have a charge of -1 and when they combine to form the formula their charges get criss crossed and we will get Mg_{1}Cl_{2} or MgCl_{2}

When an alkaline earth metal, A, reacts with a halogen, X, the formula of the Ionic compound formed should be AX_{2}


3 0
3 years ago
Which of the following is a compound that contains 2 different elements?
AfilCa [17]
Chlorine is the correct answer so A
7 0
3 years ago
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