101pex1sol - Chemistry 101 Su08 Solutions for Practice...

Info icon This preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chemistry 101 - Su08 Solutions for Practice Midterm 1 1) The symbols for silicon, arsenic, bromine, barium and cobalt are: Si, As, Br, Ba, Co E 2) Mixtures must contain two or more different substances. These substances can be elements (atomic or molecular) or compounds . There are essentially two types of mixtures, homogeneous and heterogeneous. The substances in a mixture can be separated into pure substances by physical means. Homogeneous mixtures are uniform throughout and have the same physical and chemical properties throughout. These are often referred to as solutions . Heterogeneous mixtures have physical and chemical properties that are NOT uniform throughout the sample. Heterogeneous mixtures may contain elements and may contain three substances (at least 2 or more). Pure substances are not mixtures. They are elements or compounds . They can not be separated into simpler substances through physical means but can be chemically decomposed into simpler pure substances. A pure substance can contain more than one type of atom. Table salt (NaCl) is a pure compound. Compounds are always composed of two or more different elements in fixed proportion by mass. If only one substance is present the material is a pure substance and the material must be uniform throughout (homogeneous). Both pure substances and solutions have properties that are uniform throughout. D 3) Sulfur (S), Xenon (Xe) and Phosphorus (P) are nonmetals. Lithium (Li) and Indium (In) are representative metals. Copper (Cu) and Platinum (Pt) are transition metals. Arsenic (As) and Antimony (Sb) are semimetals (metalloids). B (3 nonmetals and 2 semimetals)
Image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
4) Physical properties of Sulfur: A. Its melting point is 112 °C B. It is a yellow solid D. Its density is 2.97 g/cm 3 Physical properties depend only on the substance itself and are properties that can be measured without changing the chemical identity of the substance. Chemical properties describe how a substance changes during a chemical reaction (i.e. How it reacts and what it reacts with.) E 5) The significant figures in a measured number include all the certain digits plus 1 extra digit (the last digit shown on the right) which is estimated. All non zero digits in a number are significant. Zeros in a quantity may or may not be significant. Leading zeros (zeros before first nonzero digit) are not significant (0.001 has 1 s.f.). Captive zeros (zeros between other nonzero numbers) are significant (1.001 has 4 s.f.). Trailing zeros are significant if they follow a nonzero digit to the right of the decimal point (1.10 has 3 s.f.).
Image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern