Atomic radiusa. increases across a period and increases down a group.
b. decreases across a period but increases down a group.
c. increases across a period but decreases down a group.
d. decreases across a period and decreases down a group.

Answer : The number of moles of hydrogen gas needed are, 0.253 mole

Explanation : Given,

Moles of water = 0.253 mole

Now we have to calculate the moles of hydrogen gas.

The given balanced chemical reaction is,

From the balanced reaction we conclude that,

As, 2 moles of water obtained from 2 moles of hydrogen gas

So, 0.253 moles of water obtained from of hydrogen gas

Therefore, the number of moles of hydrogen gas needed are, 0.253 mole

Answer:

C15H24O

Explanation:

TO GET THE EMPIRICAL FORMULA, WE NEED TO KNOW THE MASSES AND CONSEQUENTLY THE NUMBER OF MOLES OF EACH OF THE INDIVIDUAL CONSTITUENT ELEMENTS.

FIRSTLY, WE CAN GET THE MASS OF THE CARBON FROM THAT OF THE CARBON IV OXIDE. WE NEED TO KNOW THE NUMBER OF MOLES OF CARBON IV OXIDE GIVEN OFF. THIS CAN BE CALCULATED BY DIVIVDING THE MASS BY THE MOLAR MASS OF CARBON IV OXIDE. THE MOLAR MASS OF CARBON IV OXIDE IS 44G/MOL

HENCE, THE NUMBER OF MOLES OF CARBON IV OXIDE IS 4.122/44 WHICH EQUALS 0.094. SINCE THERE IS ONLY ONE ATOM OF CARBON IN CO2 THEN THEY HAVE EQUAL NUMBER OF MOLES AND THUS THE NUMBER OF MOLES OF CARBON IS 0.094. WE CAN THEN PROCEED TO CALCULATE THE MASS OF CO2 PRESENT. THIS CAN BE CALCULATED BY MULTIPLYING THE NUMBER OF MOLES BY THE ATOMIC MASS UNIT. THE ATOMIC MASS UNIT OF CARBON IS 12. HENCE, THE MASS OF CO2 PRESENT IS 12 * 0.094 = 1.128g

WE CAN NOW GET THE MASS OF THE HYDROGEN BY MULTIPLYING THE NUMBER OF MOLES OF WATER BY 2 AND ALSO ITS ATOMIC MASS UNIT

TO GET THE NUMBER OF MOLES OF WATER, WE SIMPLY DIVIDE THE MASS BY THE MOLAR MASS. THE MOLAR MASS OF WATER IS 18g/mol.  The NUMBER OF MOLES IS THUS 1.350/18 = 0.075

THE NUMBER OF MOLES OF HYDROGEN IS TWICE THAT OF WATER SINCE IT CONTAINS 2 ATOMS PER MOLECULE OF WATER. ITS NUMBER OF MOLES IS THUS 0.075*2 = 0.15 MOLE

THE MASS OF HYDROGEN IS THUS 0.075 * 2 * 1 = 0.15g

WE CAN NOW FIND THE MASS OF OXYGEN BY SUBTRACTING THE MASSES OF HYDROGEN AND CARBON FROM THE TOTAL MASS.

MASS OF OXYGEN = 1.376-0.15-1.128 = 0.098g

THE NUMBER OF MOLES OF OXYGEN IS THUS 0.098/16 = 0.006125

WE CAN NOW USE THE NUMBER OF MOLES TO OBTAIN THE EMPIRICAL FORMULA.

WE DO THIS BY DIVIDING EACH BY THE SMALLEST NUMBER OF MOLES WHICH IS THAT OF THE OXYGEN.

C = 0.094/0.006125 = 15

H = 0.15/0.006125 = 24

O = 1

THE EMPIRICAL FORMULA IS THUS C15H24O

The combustion of 1.376 g of butylated hydroxytoluene (BHT) produced 4.122 g CO2 and 1.350 g H2O. Calculations yield an empirical formula of CH2O, indicating one carbon, two hydrogen, and one oxygen atom.

To determine the empirical formula of butylated hydroxytoluene (BHT), we can follow these steps:

1. **Find moles of CO2 and H2O produced:**

  \[ \text{moles of } CO_2 = \frac{\text{mass of } CO_2}{\text{molar mass of } CO_2} \]

  \[ \text{moles of } H_2O = \frac{\text{mass of } H_2O}{\text{molar mass of } H_2O} \]

2. **Find the mole ratio:**

  Divide the moles of each element (C, H, and O) in CO2 and H2O by the smallest number of moles.

3. **Write the empirical formula:**

  Use the mole ratios to write the empirical formula.

Let's perform the calculations:

\[ \text{Molar mass of } CO_2 = 12.01 \, \text{(C)} + 2 \times 16.00 \, \text{(O)} = 44.01 \, \text{g/mol} \]

\[ \text{Molar mass of } H_2O = 2 \times 1.01 \, \text{(H)} + 16.00 \, \text{(O)} = 18.02 \, \text{g/mol} \]

\[ \text{moles of } CO_2 = \frac{4.122 \, \text{g}}{44.01 \, \text{g/mol}} \approx 0.0938 \, \text{mol} \]

\[ \text{moles of } H_2O = \frac{1.350 \, \text{g}}{18.02 \, \text{g/mol}} \approx 0.0749 \, \text{mol} \]

Divide by the smallest number of moles (0.0749) to get a ratio close to 1:1:

\[ \text{C} : \text{H} : \text{O} \approx 1.25 : 1 : 1 \]

The ratio is approximately 1:1:1, so the empirical formula is CH2O.

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Word Equation: Calcium chloride + Silver nitrate → Calcium nitrate + Silver chloride (precipitate).

Type of Reaction: Double displacement (precipitation).

The chemical equation can be converted into a word equation as follows:

Word Equation:

Calcium chloride (aqueous) + Silver nitrate (aqueous) → Calcium nitrate (aqueous) + Silver chloride (solid)

Type of Reaction:

This is a double displacement reaction, specifically a precipitation reaction. In a double displacement reaction, the cations and anions of two compounds switch places, resulting in the formation of two new compounds. In this particular case, when calcium chloride and silver nitrate are mixed, calcium nitrate and silver chloride are formed.

Furthermore, it's a precipitation reaction because one of the products, silver chloride, is insoluble in water and forms a solid (precipitate) rather than remaining in solution. The solid silver chloride is observed as a white, cloudy precipitate that settles at the bottom of the reaction vessel.

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The question probable may be;

CaCl2(aq) + 2AgNO3(aq)) → Ca(NO3)2(aq) + 2AgCl(s)

Convert this into word equation and tell what type of reaction is this?