The atomic number of calcium is 20. How many protons does it have?

Answer:

12 mi/h

Explanation:

Step 1: Given data

Step 2: Convert "d" to miles

We will use the conversion factor 1 mi = 1.60934 km.

6 km × 1 mi/1.60934 km = 3.7 mi

Step 3: Convert "t" to hours

We will use the conversion factor 1 h = 60 min.

19 min × 1 h/60 min = 0.32 h

Step 4: Calculate the average speed of the runner (s)

The speed is equal to the quotient between the total distance and the time elapsed.

s = d/t

s = 3.7 mi/0.32 h = 12 mi/h

Answer: 4873200 kg

Explanation:

Given mass: [tex]1.572\times 10^8[/tex] troy oz

Conversion factor : [tex]1troyoz=0.031kg[/tex]

Thus if 1 troy oz weighs in kg = 0.031 kg

[tex]1.572\times 10^8[/tex] troy oz will weigh in kg =[tex]\frac{0.031}{1}\times 1.572\times 10^8=0.04873\times 10^8kg[/tex]

Thus there are [tex]0.04873\times 10^8kg[/tex] in [tex]1.572\times 10^8[/tex] troy oz of silver used.

Answer:

You could test for energy levels or the amount of times you can do a specific excersice.

Answer:

Simard planted paper birch, fir, and cedar trees in a plot and then injected them with different radioactive isotope carbon dioxide gases and covered them with bags. She waited an hour, then checked the trees for radiation.

Answer:

1.389 moles

Explanation:

We are given that

Given mass of ammonium=25.0 g

We have to find the  number of moles in 25.0g of ammonium.

The chemical formula of ammonium [tex]NH^{+}_4[/tex]

Molar mass of N=14, Molar mass of H=1

Molar mass of ammonium (NH4+)=14+4(4)=18 g/mol

We know that

Number of moles=Given mass/Molar mass

Using the formula

Number of moles of ammonium=[tex]\frac{25}{18}[/tex]moles

Number of moles of ammonium=1.389 moles

Hence, the number of moles in 25.0g of ammonium=1.389 moles

Answer:

Explanation:

Atoms of an element with the same mass number make up an isotope of the element. Different isotopes of the same element cannot have the same mass number, but isotopes of different elements often do have the same mass number, e.g., carbon-14 (6 protons and 8 neutrons) and nitrogen-14 (7 protons and 7 neutrons).

Answer: NO I know sorry

Answer: A. C2H3F

Explanation:

Answer:

ethical and aesthetic services and direct services

Explanation:

I just took the test and it's NOT indirect services and direct services like the other person said. It's ethical and aesthetic services and direct services.

Answer:

his mother died i think

Explanation:

Although he was not accepted, his mother was determined to give her son a first-class education and they walked to St. Petersburg. Dmitri was accepted into the Institute of Pedagogy on a full scholarship. That same year his mother died and at the age of sixteen, Dmitri was orphaned.

Answer:

Gravity is normal...

Explanation:

Objects with more mass have more gravity. Gravity also gets weaker with distance. So, the closer objects are to each other, the stronger their gravitational pull is. Earth's gravity comes from all its mass. So, theoretically speaking planets move or get pulled due to their huge amount of mass.

Answer:

Explanation:The major goals of the two rovers, according to NASA, were to determine whether life as we know it could ever have arisen on Mars (focusing particularly on searching for ancient water) and characterizing the climate and geology of  

Answer:

The major goals of the two rovers, according to NASA, were to determine whether life as we know it could ever have arisen on Mars (focusing particularly on searching for ancient water) and characterizing the climate and geology of  the planet

Answer:

snow, hail, rain

Explanation:

precipitation is the transfer of water in any form from the atmosphere to the land or sea surface

Forms of Precipitation. It can be liquid or solid; the main precipitation types are rain, sleet, snow, ice pellets, hail, and drizzle.

There are different forms of precipitation based on atmospheric conditions. Warmer atmospheric conditions might result in rain, drizzle, or hail (if it's a thunderstorm). Colder atmospheric conditions might result in snow, sleet, freezing rain, or ice crystals.

The four main types of precipitation are rain, snow, sleet, and hail. Rain is liquid precipitation that falls during many parts of the year. Hail is associated with thunderstorms and generally falls in warmer temperatures. Snow and sleet are frozen and generally fall in colder temperatures.

Learn more about different forms of precipitation at

https://brainly.com/question/866725

#SPJ2

Answer:

You have to prepare for the lab (Materials, work, paper etc.)

Set up the lab know where the lab will be taking place

Read thru the experiment before doing the lab

Make a hypothesis

Write down notes, observations, measures anything important to help with the lab!

Answer:

20 hydrogen atoms

Explanation:

Let us carefully observe the words of the question. We were told that the compound is a hydrocarbon. This implies that it is composed of only hydrogen and carbon.

Secondly, we are informed that the compounds is composed of only C-C single covalent bonds. This means that the compound is an alkane.

Then we are told that it contains nine carbon atoms and is a linear molecule. Hence, the compound must be n-nonane.

Recall that for alkanes, the general molecular formula is CnH2n+2 Substituting n=9 for nonane we have; C9H(2*9)+2 which is C9H20.

Thus there are 20 hydrogen atoms. The structure of the compound is attached to this answer

Answer:

28 g of CaO

Explanation:

We'll begin by writing the balanced equation for the reaction. This is illustrated:

CaCO₃ —> CaO + CO₂

Next, we shall determine the mass of CaCO₃ that decomposed and the mass of CaO produced from the balanced equation. This can be obtained as follow:

Molar mass of CaCO₃ = 40 + 12 + (16×3)

= 40 + 12 + 48

= 100 g/mol

Mass of CaCO₃ from the balanced equation = 1 × 100 = 100 g

Molar mass of CaO = 40 + 16

= 56 g/mol

Mass of CaO from the balanced equation = 1 × 56 = 56 g

SUMMARY:

From the balanced equation above,

100 g of CaCO₃ decomposed to produce 56 g of CaO.

Finally, we shall determine the mass of CaO that will be obtained by the decomposition of 50 g of CaCO₃. This can be obtained as follow:

From the balanced equation above,

100 g of CaCO₃ decomposed to produce 56 g of CaO.

Therefore, 50 g of CaCO₃ will decompose to produce = (50 × 56)/100 = 28 g of CaO.

Thus, 28 g of CaO were obtained from the reaction.

Complete question is;

Chemical reactivity of alkali metals increases down the group while reactivity of halogens decreases down the group. Give reasons

Answer:

Explained below

Explanation:

Alkali metals exhibit reactivity due to their electropositivity. Now, for alkalis, their electro-positivity increases down their group. Since their reactivity increases with increase in electropositivity, it means their reactivity also increases down the group.

Whereas, the reactivity of halogens occurs as a result of their electronegativity. Now, electronegativity for halogens decreases down the group. Since their reactivity decreases with decrease in electronegativity, it means that their reactivity will also decrease down the group.

Answer:

c or b

Explanation:

the story is entertaining and it shares the teachers personal experiences with the teachers students

Answer:

I choose my table

Answer:

Molecular formula for the organic compound is:  C₉H₁₈O₃

Explanation:

We determine the combustion reaction:

CₓHₓOₓ  +  O₂  →  CO₂  +  H₂O

We don't know the subscrip of the organic compound, that's why we put x.

Notice we have C in the compound and in CO₂. Let's find out the mass of C.  1 mol of CO₂ contains 1 mol of C

Then (7.950 g /44g/mol) of CO₂ may contain ?

(7.950 g /44g/mol) represents the moles of dioxide → 0.181 moles of C

These moles came from the mass of the organic compound, the 3.498 g.

So now, we can know the subscript for C.

If 3.498 g of the compound contain 0.181 moles of C

174.27 g of the compound may contain (174.27 .  0.181)/ 3.498 = 9

Let's do the same for the H.

1 mol of water contain 2 moles of H

(3.255 g /18 g/mol) of water, may contain  ?

3.255 g /18 g/mol = 0.181 moles . 2 = 0.362 moles of H

These moles came from the mass of the organic compound, the 3.498 g.

Let's find out the subscript for H

If 3.498 g of the compound contain 0.362 moles of H

174.27 g of the compound may contain (174.27 .  0.362)/ 3.498 = 18

Organic compound is C₉H₁₈Oₓ. If the molar mass is 174.27 g we can easily determine the moles of O

12 g/mol . 9 + 1 g/mol . 18 + 16 g/mol . X = 174.27 g/mol

(174.27 g/mol - 12 g/mol . 9 - 1 g/mol . 18 ) / 16 = 3

Molecular formula for the organic compound is:  C₉H₁₈O₃.  Therefore the complete combustion reaction is:

C₉H₁₈O₃  +  12O₂  →  9CO₂  +  9H₂O

Answer:

http://www.khalidshadid.com/uploads/3/9/2/0/3920808/raymond_chang-chemistry_10th_edition.pdf

Explanation:

http://www.khalidshadid.com/uploads/3/9/2/0/3920808/raymond_chang-chemistry_10th_edition.pdf

Answer:

2.6  moles of HCl will produce moles of H2 =  [tex]1.3[/tex]

Explanation:

Mass of HCl is 36.458 g/mol

Mass of Hydrogen is 1.00794 g/mol

The balanced equation here is

Mg + 2_HCI → _MgCl2 + H2'

2 moles of HCl produces one mole of H2

One mole of HCl will produce moles of H2 =  [tex]\frac{1}{2}[/tex]

2.6  moles of HCl will produce moles of H2 =  [tex]\frac{1}{2} * 2.6 = 1.3[/tex]

Answer:

Question 1.

a. the product of the reaction above that contains calcium is calcium chloride, CaCl₂.

b. the reactant, hydrochloric acid, HCl contains hydrogen

c. the product water, H₂O contains hydrogen

d. the reactant, calcium carbonate, CaCO₃ contains carbon

e. The product carbon (iv) oxide contains carbon

Question 2:

a. atoms of hydrogen and oxygen bonded together as a single compound known as water molecules are present at the start of the reaction

b. two molecules of water are present at the start of the reaction

c. two individual atoms of hydrogen and oxygen existing as molecules are present at the end of the reaction.

d. at the end of the reaction, two molecules of hydrogen and one molecule of oxygen are present.

Question 3:

a. total mass of products = 187 g

b. if Chinua starts with 10 g of magnesium, the same 10 g of magnesium will be found in the magnesium sulfate

Explanation:

Question 1: The equation of the reaction between calcium carbonate and hydrochloric acid is given as follows:  + 2HCl ---> CaCl₂ + H₂O + CO₂

a. the product of the reaction above that contains calcium is calcium chloride, CaCl₂.

b. the reactant, hydrochloric acid, HCl contains hydrogen

c. the product water, H₂O contains hydrogen

d. the reactant, calcium carbonate, CaCO₃ contains carbon

e. The product carbon (iv) oxide contains carbon

Question 2: the equation of the reaction in which water is broken down to hydrogen and oxygen is as follows: 2H₂O ----> 2H₂ + O₂

a. atoms of hydrogen and oxygen bonded together as a single compound known as water molecules are present at the start of the reaction

b. two molecules of water are present at the start of the reaction

c. two individual atoms of hydrogen and oxygen existing as molecules are present at the end of the reaction.

d. at the end of the reaction, two molecules of hydrogen and one molecule of oxygen are present.

Question 3: The equation of the reaction between magnesium and sulfuric acid is given as follows: Mg + H₂SO₄ ---> MgSO₄ + H₂

molar mass of Mg = 24.0 g; molar mass of H₂SO₄ = 98.0 g

a. when 37.0 g of magnesium is reacted with 150 g of H₂SO₄, the total mass of products of the reaction is equal to the total mass of the reactants according to the law of conservation of mass.

Total mass of products  = 150 + 37 = 187 g

b. if Chinua starts with 10 g of magnesium, the same 10 g of magnesium will be found in the magnesium sulfate

Answer:

48.0 grams

Explanation:

The products of this reaction are nitrogen gas and water. How many grams of sodium hydroxide (NaOH) are needed to completely react with 50.0 grams of sulfuric acid (H2SO4) to form sodium sulfate (Na2SO4) and water? 2NaOH + H2SO4 → Na2SO4 + 2H2O ; 48.0 grams of NaOH are needed.

51.020  grams of sodium hydroxide is needed to completely react with 50 grams of sulfuric acid according to stoichiometry.

It is the determination of proportions of elements or compounds in a chemical reaction. The related relations are based on law of conservation of mass and law of combining  weights and volumes.

Stoichiometry is used in quantitative analysis for measuring concentrations of substances present in the sample.

The reaction between sodium hydroxide and sulfuric acid is as follows,

2 NaOH + H₂SO₄[tex]\rightarrow[/tex]Na₂SO₄+2 H₂O

From the reaction, it is clear  that 2 oles of sodium hydroxide react with 1 mole of sulfuric acid to give products. According to molar mass concept,

100 g of sodium hydroxide gives 98 g of sulfuric acid

Therefore, 50 gram of sulfuric acid requires 50×100/98=51.020 g

Learn more about  stoichiometry ,here:

https://brainly.com/question/28780091

#SPJ2

Answer:

C5H12 + 8O2 --> 5CO2 + 6H2O

Explanation:

Complete question

Write a balanced chemical equation to represent the combustion of CH3CH2CH2CH2CH3

Solution

The given compound is pentane

C5H12

The empirical equation representing combustion of pentane is

C5H12 + O2 --> CO2 + H2O

We will first balance the carbon atoms

C5H12 + O2 --> 5CO2 + H2O

Now we will balance the Hydrogen molecule

C5H12 + O2 --> 5CO2 + 6H2O

Now we will balance the oxygen molecule

C5H12 + 8O2 --> 5CO2 + 6H2O

Answer:

Ethanol is soluble in water because it has a hydroxyl group which allows it to form hydrogen bonds with the water molecules. This is why hexanol is not soluble in water.

Answer:

D) 3.51x10²³ formula units

Explanation:

To know this, we need to calculate the molecular mass of CaO. To do that, let's use the atomic mass of each element of this compound.

Ca: 40.08 g/mol;    O: 16 g/mol

With these given AM, let's calculate the molar mass of CaO:

Mm CaO = 40.08 + 16 = 56.08 g/mol

Now that we have the MM of CaO, it's time to determine the moles of CaO:

moles = mass / MM

moles = 32.7 / 56.08 = 0.5831 moles

Finally to get the formula units, we need to use the Avogadro's number which is 6.02x10²³. According to this number, 1 mole of any substance has this number of atoms, molecules or formula units. So, if we have 0.5831 moles, then the formula units will be:

FU = 0.5831 * 6.02x10²³

Hope this helps

Answer:

Alkylenes: any of the series of unsaturated hydrocarbons containing a triple bond, including acetylene.

alkanes​: Alkanes are organic compounds that consist entirely of single-bonded carbon and hydrogen atoms and lack any other functional groups. Alkanes have the general formula CnH2n+2 and can be subdivided into the following three groups: the linear straight-chain alkanes, branched alkanes, and cycloalkanes.

Explanation: