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3 years ago

Significant Figures For 7.06 × 10^5 ÷ 5.3 × 10^-2

Chemistry

1 answer:

Kay [80]3 years ago

4 0

Answer:

$\boxed{\text{two}}$

Explanation:

In multiplication and division problems, your answer can have no more significant figures than the number with the fewest significant figures.

$\dfrac{7.06 \times 10^{5}}{5.3 \times 10^{-2}}= 1.332 075 472 \times 10^{7}$ (by my calculator)

There are three significant figures in 7.06 and two in 2.3.

You must round to $\boxed{\textbf{two}}$ significant figures and report the answer as 1.3 × 1.0⁷.

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Complete combustion of 7.40 g of a hydrocarbon produced 22.4 g of CO2 and 11.5 g of H2O. What is the empirical formula for the h

cluponka [151]

C2H5 First, you need to figure out the relative ratios of moles of carbon and hydrogen. You do this by first looking up the atomic weight of carbon, hydrogen, and oxygen. Then you use those atomic weights to calculate the molar masses of H2O and CO2. Carbon = 12.0107 Hydrogen = 1.00794 Oxygen = 15.999 Molar mass of H2O = 2 * 1.00794 + 15.999 = 18.01488 Molar mass of CO2 = 12.0107 + 2 * 15.999 = 44.0087 Now using the calculated molar masses, determine how many moles of each product was generated. You do this by dividing the given mass by the molar mass. moles H2O = 11.5 g / 18.01488 g/mole = 0.638361 moles moles CO2 = 22.4 g / 44.0087 g/mole = 0.50899 moles The number of moles of carbon is the same as the number of moles of CO2 since there's just 1 carbon atom per CO2 molecule. Since there's 2 hydrogen atoms per molecule of H2O, you need to multiply the number of moles of H2O by 2 to get the number of moles of hydrogen. moles C = 0.50899 moles H = 0.638361 * 2 = 1.276722 We can double check our math by multiplying the calculated number of moles of carbon and hydrogen by their respective atomic weights and see if we get the original mass of the hydrocarbon. total mass = 0.50899 * 12.0107 + 1.276722 * 1.00794 = 7.400185 7.400185 is more than close enough to 7.40 given rounding errors, so the double check worked. Now to find the empirical formula we need to find a ratio of small integers that comes close to the ratio of moles of carbon and hydrogen. 0.50899 / 1.276722 = 0.398669 0.398669 is extremely close to 4/10, so let's reduce that ratio by dividing both top and bottom by 2 giving 2/5. Since the number of moles of carbon was on top, that ratio implies that the empirical formula for this unknown hydrocarbon is C2H5

3 0

3 years ago

Can someone help Plz

Marrrta [24]

Answer: A. 1.60 liters

Explanation:

$2Na_2O_2+2CO_2\rightarrow 2Na_2CO_3+O_2$

As can be seen from the balanced chemical equation, 2 moles of $CO_2$ produce 1 mole of $O_2$ .

According to Avogadro's law, every 1 mole of the gas occupies 22.4 liters at STP.

Thus $2$ moles of $CO_2$ occupies $22.4\times 2=44.8L$ at STP and produce 1 mole of $O_2$ i.e. 22.4 L

44.8 L of $CO_2$ will produce 22.4 L of $O_2$

Thus $3.20L$ of $CO_2$ will produce $\frac{22.4}{44.8}\times 3.20=1.60L$

6 0

2 years ago

Calculate the atomic mass of gallium, symbol Ga. Gallium has two isotopes: Ga-69 and Ga-71. The relative abundance of Ga-69 is 6

amm1812

Answer:

The atomic mass of gallium (Ga) = 69.723 g/mol

Explanation:

Given: Two isotopes of Gallium (Ga) are Gallium-69 (⁶⁹Ga) and Gallium-71 (⁷¹Ga)

For ⁶⁹Ga: 

Relative abundance = 60.12% = 60.12 ÷ 100 = 0.6012; Atomic mass = 68.9257 g/mol

For ⁷¹Ga:

Relative abundance = 39.88% = 39.88 ÷ 100 = 0.3988; Atomic mass = 70.9249 g/mol

∴ The atomic mass of Ga = (Relative abundance of ⁶⁹Ga × Atomic mass of ⁶⁹Ga) + (Relative abundance of ⁷¹Ga × Atomic mass of ⁷¹Ga)

⇒ Atomic mass of Ga = (0.6012 × 68.9257 g/mol) + (0.3988 × 70.9249 g/mol) = 69.723 g/mol

Therefore, the atomic mass of gallium (Ga) = 69.723 g/mol

8 0

3 years ago

The analysis of a compound gives the following percent composition by mass:

boyakko [2]

Answer:

C15 H31 O4 S

Explanation:

molecular formula is also the same because the value of "n" is 1

5 0

2 years ago

What is the charge on an ion that has an atomic number of 16 and contains 14e-?

lora16 [44]

The answer would be 2+ since the atomic number represents how many protons are in the element. In this case, there are 16 protons, but only 14 electrons, which means there are an additional 2 protons, hence the 2+ charge on the ion.

3 0

2 years ago