SigFigs
12.56 + 0.438 + 102.1
115.1
Convert 20 kg to g
20000 g
Trail mix is a heterogenous or homogenous mixture?
heterogenous mixture
Write the formula for calcium chloride.
What subatomic particle has a positive charge?
proton
(6.25*4.0)/1.50
17
How many atoms are in 44.0 g of CO2?
1.81*10^24
When mixing salt in water until completely dissolved, what type of mixture is this?
Name Al2O3
Aluminum oxide
What determines the chemical identity of an element?
The atomic #/# of protons
Round 0.0134457 to 5 sigfigs.
0.013446
A sample has a mass of 23.453 g H2SO4. H2SO4 has a molar mass of approximately 98.08 g/mol. How many mols are present?
0.2391 mol H2SO4
Classify oxygen gas (O2) as a pure substance, homogeneous mixture, or heterogeneous mixture.
Pure substance
Name FeCl3
Iron (III) chloride
Atoms of the same element that have a different number of neutrons are:
isotopes
Convert 9408.715 to scientific notation.
9.408715*10^3
When heated to 300oC, solid sodium azide (NaN3) decomposes to form gaseous nitrogen and solid sodium. If 1.69×10 27 formula units of sodium azide completely react, how many moles of nitrogen are produced?
4.21*10^3 mol N2
A container contains 9.1038 g of xenon (a colorless gas) were combined in a previously evacuated container with 0.927 g of fluorine (a pale yellow gas). This reaction produces 4.13102 g of a white solid. If all of the fluorine is consumed, what mass of xenon remains unreacted?
5.900 g Xe
When solid iron(III) oxide is reacted with gaseous carbon monoxide, solid iron and gaseous carbon dioxide are produced. Write a balanced chemical equation for this reaction
Fe2O3 (s) + 3CO (g) -> 2Fe (s) + 3CO2 (g)
Who conducted the gold foil experiment that proves atoms contain a small, dense, positively charged nucleus.
Ernest Rutherford
((7.8*10^3)/(2.10*10^2)) + 1.25
38
Phosphoric acid reacts with magnesium hydroxide to produce magnesium phosphate and water. What volume of 8.235 M phosphoric acid, in mL, is necessary to completely react with 70.00 mL of 2.75 M magnesium hydroxide?
15.6 mL
Combustion of gaseous ethylene (C2H4) involves reacting ethylene with oxygen in the air. Combustion of ethylene produces the gases carbon dioxide and water. Write a balanced chemical equation for the combustion of ethylene.
C2H4 (g) + 3O2 (g) -> 2CO2 (g) + 2H2O (g)
When liquid silicon tetrachloride is added to liquid water a chemical reaction occurs. The products of this chemical reaction are solid silicon dioxide and gaseous hydrogen chloride. Write a balanced chemical equation for this reaction
SiCl4 (l) + 2H2O (l) -> SiO2 (s) + 4HCl (g)
Who conducted the cathode ray experiment that proved the existence of the electron?
J. J. Thomson