How many significant figures are in 0.00120

Morgarella [4.7K]

The answer to this is "D" The reason it is not "C" is because some steroids are used to treat medical issues, and others are used for the purpose of repairing the muscle faster after working out such as anabolic steroid

5 0

3 years ago

( This is for science ) If part “d” of a wave is changed it changes the ____.

Feliz [49]

wavelength i think should be correct

4 0

3 years ago

Now if your lab partner determined that there were 1.552 x 1022 atoms of H in an unknown sample of C2H4Cl2, how many milligrams

STALIN [3.7K]

To determine the mass of the sample in milligrams in this problem, we use the avogadro's number to convert from atoms to moles, relate the moles of element in the sample to the mole present and the molar mass of the sample. We do as follows:

1.552 x 10^22 atoms H ( 1 mol H / 6.022x10^23 atoms H ) ( 1 mol C2H4Cl2 / 4 mol H ) ( 98.96 g C2H4Cl2 / 1 mol C2H4Cl2 ) = 0.625 g C2H4Cl2 = 625 mg C2H4Cl2

3 0

4 years ago

The equations are 2NaHCO3 -> Na2CO3 + CO2 + H20, NaHCO3 -> NaOH + CO2, 2NaHCO3 -> Na2O + 2CO2 + H20

cricket20 [7]

Answer:

The product made is Na2CO3.

The % yield is 91.8 %

Explanation:

Step 1: Data given

Mass of baking soda (NaHCO3) = 5.0 grams

Molar mass of NaHCO3 = 84.0 g/mol

Each of the equations calculated is left with 2.4g of NaOH, 1.86 g Na2O, and 3.18g Na2Co3.

Step 2: The balanced equations

2NaHCO3 → Na2CO3 + CO2 + H20

NaHCO3 → NaOH + CO2

2NaHCO3 → Na2O + 2CO2 + H20

Step 3: Calculate moles NaHCO3

Moles NaHCO3 = mass NaHCO3 / molar mass NaHCO3

Moles NaHCO3 = 5.0 grams / 84.0 g/mol

Moles NaHCO3 = 0.060 moles

Step 4: Calculate moles of products

For 2 moles NaHCO3 we'll have 1 mol Na2CO3

For 0.060 moles NaHCO3 we'lll have 0.060 / 2 = 0.030 moles Na2CO3

For 1 mol NaHCO3 we'll have 1 mol NaOH

For 0.060 moles NaHCO3 we'll have 0.060 moles NaOH

For 2 moles NaHCO3 we'll have 1 mol Na2O

For 0.060 moles NaHCO3 we'll have 0.030 moles Na2O

Step 5: Calculate mass of products

Mass = moles * molar mass

Mass of Na2CO3 = 0.030 moles * 105.99 g/mol = 3.18 grams

Mass of NaOH = 0.060 moles * 40.0 g/mol = 2.4 grams

Mass of Na2O = 0.030 moles *61.98 g/mol = 1.86 grams

Step 6: Calculate the percent yield

% yield = actual yield / theoretical yield

% yield Na2CO3 = (2.92 grams / 3.18 grams) *100% = 91.8 %

% yield NaOH = (2.92 grams / 2.4 grams ) *100% = 121.6 %

% yield of Na2O = (2.92 grams / 1.86 grams ) * 100% = 157 %

The product made is Na2CO3, the other reactions have a % yield greater than 100 %

7 0

3 years ago

Why would it probably be very difficult to determine the chemical and physical properties of a newly discovered synthetic elemen

Alex17521 [72]

With newly discovered materials, nothing is yet know about them. Scientists don't know how to conduct physical/chemical experiments without damaging the element. Lethal substances or corrosive materials can be set off from combustion or decomposition. It would be difficult to determine the properties because no one knows what the element is made of. Chemical properties are often characterized by reactivity with other chemicals, such as toxicity, coordination number, flammability, enthalpy of formation, the heat of combustion, and oxidation states. It is difficult to measure those things when you have no idea what an element may be giving off.

6 0

3 years ago