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netineya [11]
2 years ago
5

Which statement best describes perigee? A. The Sun's orbit that is closest to the Moon End of exam B. The closest point in Earth

's orbit of the Sun C. The farthest point in the Moon's orbit to Earth D. The closet point in the Moon's orbit to Earth
Chemistry
1 answer:
zhenek [66]2 years ago
6 0

Answer:

The closet point in the Moon's orbit to Earth

Explanation:

In the Moon's ellipticalorbit around Earth the closest

point of the orbit to the Earth is called the perigee, in the same light, point farthest in the Moon's orbit from Earth is known as apoge

You might be interested in
Hc1 is the formula for .
PIT_PIT [208]

Answer:

HCl is the formula for Hydrochloric acid

Explanation:

  • Chemical formula is a formula of a compound showing the symbols of elements present in the compound.
  • Chemical formula also shows the number of atoms of each element present in a compound.
  • HCl is the chemical formula of hydrochloric acid. From this formula we can tell that hydrochloric acid is made up of hydrogen and chlorine elements.
  • The formula also shows that HCl contains 1 hydrogen atom and 1 chlorine atom.
5 0
3 years ago
Sodium acetate can be formed from the metathesis/double replacement reaction of sodium
telo118 [61]

Answer:

Explanation:

Sodium Acetate Trihydrate BP Specifications

Sodium Acetate BP

C2H3NaO2,3H2O

Action and use

Used in solutions for dialysis; excipient.

DEFINITION

Sodium ethanoate trihydrate.

Content

99.0 per cent to 101.0 per cent (dried substance).

CHARACTERS

Appearance

Colourless crystals.

Solubility

Very soluble in water, soluble in ethanol (96 per cent).

IDENTIFICATION

A. 1 ml of solution S (see Tests) gives reaction (b) of acetates.

B. 1 ml of solution S gives reaction (a) of sodium.

C. Loss on drying (As shown in the Relevant Test).

TESTS

Solution S

Dissolve 10.0 g in carbon dioxide-free water prepared from distilled water R and dilute to 100 ml 100 ml with the same solvent.

Appearance of solution

Solution S is clear and colourless.

pH

7.5 to 9.0.

Dilute 5 ml of solution S to 10 ml with carbon dioxide-free water.

Reducing substances

Dissolve 5.0 g in 50 ml of water, then add 5 ml of dilute sulphuric acid and 0.5 ml of 0.002 M potassium permanganate. The pink colour persists for at least 1 h. Prepare a blank in the same manner but without the substance to be examined.

Chlorides

Maximum 200 ppm.

Sulphates

Maximum 200 ppm.

Aluminium

Maximum 0.2 ppm, if intended for use in the manufacture of dialysis solutions.

Arsenic

Maximum 2 ppm, determined on 0.5 g.

Calcium and magnesium

Maximum 50 ppm, calculated as Ca.

Heavy metals

Maximum 10 ppm.

Iron

Maximum 10 ppm, determined on 10 ml of solution S.

Loss on drying

39.0 per cent to 40.5 per cent, determined on 1.000 g by drying in an oven at 130C.

Sodium Acetate FCC Food Grade, US Food Chemical Codex

C2H3NaO2 Formula wt, anhydrous 82.03

C2H3NaO2·3H2O Formula wt, trihydrate 136.08

DESCRIPTION

Sodium Acetate occurs as colorless, transparent crystals or as a granular, crystalline or white powder. The anhydrous form is hygroscopic; the trihydrate effloresces in warm, dry air. One gram of the anhydrous form dissolves in about 2 mL of water; 1 g of the trihydrate dissolves in about 0.8 mL of water and in about 19 mL of alcohol.

Function: Buffer.

REQUIREMENTS

Identification: A 1:20 aqueous solution gives positive tests for Sodium and for Acetate.

Assay: Not less than 99.0% and not more than 101.0% of C2H3NaO2 after drying.

Alkalinity Anhydrous: Not more than 0.2%; Trihydrate: Not more than 0.05%.

Lead: Not more than 2 mg/kg.

Loss on Drying: Anhydrous: Not more than 1.0%; Trihydrate: Between 36.0% and 41.0%.

Potassium Compounds: Passes test.

5 0
3 years ago
Please help
lisabon 2012 [21]

Answer:

There are 2 hydrogen atoms, one magnesium atom, and 5 atoms in total.

Explanation:

We are given a compound in formula form. To make things easier to understand, we can first convert this to the name of the compound.

  • When a compound contains one or more elements in parentheses, these are usually a <u>polyatomic ion</u>.
  • Polyatomic ions are ions made up of two or more elements with a positive or negative charge over the entire ion. Commons examples of these NH₄⁺ (ammonia) and HCO₃⁻ (bicarbonate).
  • You can combine metals with polyatomic ions to create commonly known compounds, such as baking soda. The chemical name for baking soda is sodium bicarbonate, so we can combine Na (sodium) with HCO₃⁻ (bicarbonate) and create sodium bicarbonate: NaHCO₃.

This compound is one magnesium atom bonded to two hydroxide ions.

  • Hydroxide is the compound between one hydrogen atom and one oxygen atom. The compound overall adopts a negative charge of 1.
  • If we have one hydrogen atom and one oxygen atom, the most electronegative atom is written first in chemical formulas. Therefore, the symbol for Oxygen (O) goes first.
  • Then, write in the hydrogen atom directly after the O symbol: OH.
  • Finally, since we have a negative charge on the ion, we need to play a negative sign as a superscript for the compound. Therefore, this becomes OH⁻.

Now, we need to determine the charge on the Magnesium atom which is determined from the amount of valence electrons the atom has.

  • On a periodic table, the symbol for Magnesium is Mg and this element has 2 valence electrons.
  • In order to fulfill the Octet Rule, the It is more likely to give up 2 electrons to a nonmetal than it is to gain 6, so we can safely assume that the charge is ²⁺.
  • We need to use the criss-cross technique to transfer the charges between the element and the ion, so the negative 1 charge goes to the Mg, which does not appear (negative 1 or positive 1 are implied) and since the magnesium has a charge of positive 2, this is the subscript for the hydroxide ion.
  • Therefore, our compound becomes Mg(OH)₂, and we have labeled this as magnesium hydroxide.

Now, to the number of atoms:

  • The new charge on Mg is 1-, so there is only one atom of Mg.
  • The charge is 2+ on the OH ion, so there are two atoms of H and two atoms of O.
  • Two atoms of oxygen, two atoms of hydrogen, and one atom of magnesium add up to be five atoms in total.
3 0
2 years ago
A sample of gas of 752 torr and occupies a volume of 5.12 L. What will the new volume be when the pressure is increased to 1.5 A
Katyanochek1 [597]
<span> 7.80 hop it help u ok</span>
3 0
3 years ago
An unknown compound contains only carbon and hydrogen. Combustion analysis of the compound produces 0.2845 g of carbon dioxide a
Len [333]

Answer:

C2H5

Explanation:

As the question says, the carbon from the compound is used to form carbon dioxide and the hydrogen is used to form the water, if the analysis of the compound produces 0.2845 g of and 0.1451 g and we know the molar mass of CO2 and H2O(44 and 18 (g/mol), respectively), it is possible to calculate the number of moles of CO2 and H2O.

<u>Number of moles= g/molar mass </u>

Number of moles of CO2= 0.2845g/ (44 g/mol)= 0.0065 moles of CO2, if one mole of CO2 has 1 mole of C, so <em>there are 0.0065 moles of C  </em>

Number of moles of H2O= 0.1451/(18 g/mol)= 0.0081 moles of H2O. There are two hydrogens for each water, so there are 0.0162.

<em>The empirical formula shows the ratio of the elements in the compound</em>, so it is possible to know the ratio between C and H dividing each number of moles by the smallest numer

C= 0.0065/0.0065=1

H=0.0162/0.0065=2.5

Then if we multiply by two, the empirical formula is C2H5, it is because it can´t be represented by non integer numbers.

5 0
3 years ago
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