All categories

2 years ago

Which measurement contains three significant figures?

2 answers:

8 0

The answer is C because you don’t have to worry about the number in front of the decimal unless it is something greater than zero. A- Doesn’t have there sig figs. B- The zero after the 5 doesn’t change it. D- The three at the end doesn’t matter because it does not round it up.

nadezda [96]2 years ago

3 0

A i think a is right 0.05

You might be interested in

Key terms: Reset ____________ anions are strong nucleophiles that open epoxide rings by an SN2 mechanism. ____________ tautomers

iogann1982 [59]

Answer:

Acetylide , Enol ,aldehydes, tautomers, alkynes , Hydroboration, Keto

Explanation:

Reset Acetylide anions are strong nucleophiles that open epoxide rings by an SN2 mechanism. Enol tautomers have an O-H group bonded to a C=C. aldehydes are formed from terminal alkynes with the addition of water using BH3 then H2O2. tautomers are constitutional isomers that differ in the location of a double bond and a hydrogen and exist in an equilibrium with each other. alkynes are compounds that contain a carbon-carbon triple bond. Hydroboration of a terminal alkyne adds BH₂ to the less substituted, terminal carbon. Keto tautomers have a C=O and an additional C-H bond.

3 0

3 years ago

PLEASE HELP!! PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP PLEASE HELP’

ahrayia [7]

Answer:

B is the answer because it doesn't matches the num of valence electrons

8 0

2 years ago

Read 2 more answers

Look at the model below. Which formula is best represented by this model?

Olenka [21]

The third answer because there are two of each atom

6 0

2 years ago

1) When 2.38g of magnesium is added to 25.0cm of 2.27 M hydrochloric acid, hydrogen gas is released.

Andrej [43]

Answer:

a. HCl.

b. 0.057 g.

c. 1.69 g.

d. 77 %.

Explanation:

Hello!

In this case, since the reaction between magnesium and hydrochloric acid is:

$Mg+2HCl\rightarrow MgCl_2+H_2$

Whereas there is 1:2 mole ratio between them.

a) Here, we can identify the limiting reactant as that yielded the fewest moles of hydrogen gas product via the 1:1 and 2:1 mole ratios:

$n_{H_2}^{by\ HCl}=0.025L*2.27\frac{molHCl}{1L}*\frac{1molH_2}{2molHCl} =0.0284molH_2\\\\n_{H_2}^{by\ Mg}=2.38gMg*\frac{1molMg}{24.3gMg}*\frac{1molH_2}{1molMg}=0.0979molH_2$

Thus, since hydrochloric yields fewer moles of hydrogen than magnesium, we realize it is the limiting reactant.

b) Here, we use the molar mass of gaseous hydrogen (2.02 g/mol) to compute the mass:

$m_{H_2}=0.0284molH_2*\frac{2.02gH_2}{1molH_2}=0.057gH_2$

c) Here, we compute the mass of magnesium associated with the yielded 0.0248 moles of hydrogen:

$m_{Mg}^{reacted}=0.0284molH_2*\frac{1molMg}{1molH_2}*\frac{24.3gMg}{1molMg} =0.690gMg$

Thus, the mass of excess magnesium turns out:

$m_{Mg}^{excess}=2.38g-0.690g=1.69gMg$

d) Finally, we compute the percent yield, considering 0.044 g is the actual yield and 0.057 g the theoretical yield:

$Y=\frac{0.044g}{0.057g} *100\%\\\\Y=77\%$

Best regards!

8 0

2 years ago

You find a compound composed only of element X and chlorine and you know that the compound is 13.10% X by mass. Each molecule of

8_murik_8 [283]

Answer:

Explanation:

So, the formula for the compound should be:

$XCl_{6}$

Now we assume that we have 1 mol of substance, so we can make calculations to know the molar mass of element X, as follows:

$M_{Cl}=35.45g/mol\\$

So we have that 6 moles weight 212.7g, and we can make a rule of three to know the weight of compound X:

$212.7g\rightarrow 86.9\%\\x\rightarrow 13.1\%\\\\x=\frac{212.7g*13.1}{86.9} =32.06g$

As we used 1 mol, we know that the molar mass is 32.06g/mol

So the element has a molar mass of 32.06 g/mol and an oxidation state of +6, with this information, we can assure that the element X is sulfur, so the compound is $SCl_{6}$

8 0

3 years ago