Copper samples must have 29 protons, react with oxygen, melt at 1768 K, and conduct electricity.
In order for a sample of matter to be copper, it must meet certain criteria:
Therefore, if a sample of matter meets all of these criteria, it can be identified as copper.
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87.75 grams of sodium chloride (NaCl) are required to prepare 500. mL of 3.00 M solution.
The mole is an amount unit similar to familiar units like pair, dozen, gross, etc. It provides a specific measure of the number of atoms or molecules in a bulk sample of matter.
A mole is defined as the amount of substance containing the same number of atoms, molecules, ions, etc. as the number of atoms in a sample of pure 12C weighing exactly 12 g.
Given,
Volume of NaCl = 500ml
Concentration = 3M
Moles = Concentration × volume
= 3 × 0.5
= 1.5 moles
Mass = moles × molar mass
= 1.5 × 58.5
= 87.75 g
Therefore, 87.75 grams of sodium chloride (NaCl) are required to prepare 500. mL of 3.00 M solution.
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a. mass number: 24, charge: +2
b. mass number: 22, charge: neutral
c. mass number: 34, charge: -2
d. mass number: 34, charge: +2
The mass mass number is 22 and the charge of the atom is +2. The correct answer is option A
1. The mass number of the atom can be obtained as follow:
Mass number = number of proton + number of neutron
= 12 + 12
= 24
2. The charge of the atom can be obtained as follow:
Charge = number of protons - number of electrons
= 12 - 10
= +2
Thus, the mass number is 24 and the charge is +2. The correct answer to the question is option A
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Answer: Option is the correct answer which is 4) Empirical, structural, molecular
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
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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